E38S62 Steering issue part deux!

**kotik** · 10-09-2020, 09:42 PM

Sooo, you might have seen my previous post, but i decided to make another one since it seems that the problem is something else entirely.

Car is an E38S62 swap (was listed on cars and bids). All of the front end was replaced. Brakes, i'm told, are from 750 (not sure if rotors and calipers, or just rotors). Not sure on the brake system in general (like the booster and else).

After many of you helped me with trying to diagnose the vibration issue, i went ahead and ordered new tires earlier today. This evening i had to take my girl to the airport, and she had a lot of luggage, thus i had no choice but to to take the beast.

When i pulled up to one of the lights, crawling to a stop (on the brakes), it felts like the ABS engaged

super weird, it was dry and 90F out. i immediately pulled over to investigate, to try and see whats up and noticed that my rotors were a bit too warm... but its hot out, and i did drive for 5 minutes.

I get on the highway, and i'm back to where i started with the issue. i recently bought this car, and immediately noticed that the wheel vibrates on the highway, so i had wheels balanced, and rotors cut (rotors had some minor burn marks and were a bit wavy, but looked fairly new). The suspension is all new. Initially the problem went away, but i could feel a little bit of a wobble, not very pronounced, just a tiny bit. Then the problem started to come back, slowly ... (i mostly drove the car around town and short distances). I had a shop take a look at suspension, and all seemed to be in order, except the tires didn't look too good, were a tad old and had some wave to them. So it was decided that the culprit is the tires (which i ordered this morning, after spending days researching).

So i'm on the highway, the wheel shakes at 60mph, as if the wheels are out of balance, gets better towards 70-80, but when you brake around 60-65 the wheel violently shakes (warped rotors symptoms). In the airport parking lot, i again get the same thing with the ABS, as if sliding on snow with abs on, only i'm going 3mph and its dry. On the way back from the airport, i took very good care to drive without braking, at all! I only used brakes near the house at around 4mph. I get into garage and try rotors for heat, and what do you know, the left driver side rotor is hot (not burning hot, but cant really touch it) and again has some burn marks. The passenger side is a tad warm, but could have been from my slight braking.

So, what now? sure, all new brakes would be optimal, but damn it, i just bought all 4 tires, had the rotors cut, had all wheels balanced, id like to find a reasonable solution to this. Can these calipers be repaired? maybe take the pads off, spray some silicone in there and work the pistons? Could it be the brake lines? They look to be in great condition (either newer, or maybe someone cleaned them before and painted them?). Can i cut the rotors again? They were almost new when i did it the first time. Should i replace the pads (they have like 95% life in them).

So some calipers on summit racing, $113 a pop...

thank you.

**CPHES** · 10-10-2020, 12:09 AM

With all of that, did you get an ABS dash lights, or other warning lights on the dash? If you had this all apart to look at, and from the Pics in the other thread, it looked pretty extensive. - So this is with the new tires? If you have 750 calipers, the front have 2 pistons. 740 Calipers are single piston. Easy to identify. 750 Calipers bolt up, but use 750 Rotors as well. 750 Calipers in the rear have vented rear rotors. Does the car stop at the low speed with the ABS judder, or do feel that they are not engaging?

One possible cause could be bad abs sensors, or dirty trigger wheel ( on the bearing ). off brand sensors have given trouble, or don't last long. see if you can identify the manufacturer. VDO is good. I have Delphi ones in the Mini, and they have been ok.

Shaking - something is odd. what tires did you put on ( who made them and size. Did you spin the wheels when the car is in the air to see if there is any odd runout ( side to side ) with these rims?

I'll try to think of more.

**purplecty** · 10-10-2020, 12:29 AM

What wheels are currently on the car?

**kotik** · 10-10-2020, 01:07 AM

Originally Posted by CPHES

With all of that, did you get an ABS dash lights, or other warning lights on the dash? If you had this all apart to look at, and from the Pics in the other thread, it looked pretty extensive. - So this is with the new tires? If you have 750 calipers, the front have 2 pistons. 740 Calipers are single piston. Easy to identify. 750 Calipers bolt up, but use 750 Rotors as well. 750 Calipers in the rear have vented rear rotors. Does the car stop at the low speed with the ABS judder, or do feel that they are not engaging?

One possible cause could be bad abs sensors, or dirty trigger wheel ( on the bearing ). off brand sensors have given trouble, or don't last long. see if you can identify the manufacturer. VDO is good. I have Delphi ones in the Mini, and they have been ok.

Shaking - something is odd. what tires did you put on ( who made them and size. Did you spin the wheels when the car is in the air to see if there is any odd runout ( side to side ) with these rims?

I'll try to think of more.

Thank you for a detailed response.

It had 2 pistons, so then its 750 for both the calipers and rotors. not sure on the rears, don't seem to be any issues there.

I have not installed the new tires yet, they will come next week. So still on old tires. I may have two separate issues at hand. However, after the first instance (when i first got the car), i had tires balanced, and rotors cut (which did have some burn marks, although the rotors appeared new/er otherwise). After which, i took it on the highway, and the car seemed to drive fine, no shaking on the braking, albeit small random wobble (not consistent), just felt like something was a bit off (might be the second part of the issue, the tires). After driving another 100 miles or so, i'm back where i started with vibrations, they come on around 60, die down a bit at 75-80 (but can still feel some wobble), and once i brake from 80, at 65 wheel shakes violently (warped rotors type of stuff).

no abs light, no traction light. Just felt like i was braking on snow, happened at very low speed (3-4mph), not every time, only happened twice (i tried to replicate a few times)... even my girl heard it.

stock 18 m wheels.

not sure what sensors are on.

- - - Updated - - -

just to point out, the left rotor was hot, i could barely touch it and had new burn marks (minor). the right rotor seemed warm/didn't raise a concern, didn't have burn marks.

**CPHES** · 10-10-2020, 09:24 AM

Do you have any friends with e38’s? Swap your tires with a car that has no issues. Stock 750 calipers fit under all rims - even the 16” grandpa rims. That is for the wobble issue, not the abs issue.

**kotik** · 10-11-2020, 01:17 PM

welp,

today i went to parts store to source a rebuild kit (which they didn't have), and my "bake" "abs" and "traction" lights came on....

So, i think i can still cut the rotors one more time, but what else should i do? a caliper rebuild kit (just the gaskets, or gaskets and some bolts?)? Abs sensors? Bearings?

**purplecty** · 10-11-2020, 01:41 PM

Check the ABS errors first

**Timm** · 10-11-2020, 02:35 PM

Yes, the ABS feel through the pedal is sure to be a sensor on its way out - possibly because of the heat - but INPA will show which wheel is affected

**kotik** · 10-11-2020, 03:01 PM

i figure i'll just replace both., rock auto has them for $20. They also have remanufactured calipers for $55, so i'll take two. Will see how my brake lines look, and will order those as needed. New brake fluid too.

Sounds like a good plan?

**CPHES** · 10-11-2020, 04:12 PM

No. Go to FCPEuro for the sensors. Or AutohausAZ, or ecstuning, or oembimmerparts. $20 rock auto solution is likely going to have you back in the same scene of this movie very soon. Pull the calipers, and see if you can compress the pistons easily. If you can’t, then get a rebuilt. If you can, then look at the condition of the soft line. Again - shop at the places above to source the soft line. Ate ( Alfred Teves ), and Coretco are good brands. Ate makes most of the calipers.

**kotik** · 10-11-2020, 11:16 PM

the plot thickens... well sort of.

I decided to take a look at things up close behind the wheel... everything looks new... all the lines look new, rotors look new. wtf. Of note, the ABS sensors look all black, but from what i understand post 1998 they should be blue? The car is 2000, the M5 was 2003. I would assume that the ABS system is from the 740, so prob should be blue sensors... i'm confused. Could the wrong sensors be causing issues with the ABS system? Such as causing the calipers not to release the rotor all the way? The calipers don't look old. However, at this point i can't really deduct the possibility that the driver's side got damaged due to heat (though i've never seen smoke coming from the brakes, the burn marks are minor, and it appears that it doesn't apply too much pressure, the car will roll on minor decline AND i now remembered that when i was getting wheels balanced, the guy said the wheel spins kind of hard, but was able to turn it by hand). Do ABS sensors have anything to do with how much the caliper releases the pads? Perhaps just a faulty caliper...

The weird thing is that i felt like ABS was kicking in on the passenger side, not the driver's side. Could that be due to a faulty ABS sensor on the driver's side? Per ya'll's advice, i looked at FCPEuro sensors, they are much pricier, and i'd rather not replace both if i don't have to. I'm thinking of just ordering a new caliper and a new sensor for the driver's side. Lines look new.

passenger side

Driver's side

**CPHES** · 10-12-2020, 12:22 AM

So, that ‘hard turning’ wheel - is he the hot one? Compress the pistons back into the bores - slowly, be nice. If they move easily, you can road test again. If they are sticking - yes get another caliper

**kotik** · 10-12-2020, 01:17 AM

Yes, it was the left one. But again, i'm not a 100% on the right one either, but the left one is for sureeee! So when i get the caliper off, should i try to spray silicone into it? Is it possible to salvage the ABS sensor? I saw it in one thread, that it can be taken apart and cleaned up.

I was reading this:

https://www.bimmerfest.com/threads/2...3#post-4205801

and it makes my head spin about what could all be wrong.

It just baffles me that with all parts looking so new that something is wrong. If it was an old caliper, i'd have an easier time just replacing it, but damn.. what could have caused the caliper to go a-wire. Why did all my brake/abs/traction light come on after so long? Why did it feel like abs engaged on the passenger side? Why do i have dead center on the steering wheel? Could it be related to some deeper issue with the M5 swap and signals and sensors? so many questions, sorry, i may be rambling.

**CPHES** · 10-12-2020, 08:57 AM

No Silicone on the caliper...... https://www.zeckhausen.com/catalog/i...Path=6446_6494.

you can try to save the sensor - clean it up, also use a steel brush on the outer part of the bearing that tells the sensor it is moving vs locking. It looks like a gear.

The failure mode is usually the outer dust seal getting torn, and water, dirt gets in.

**kotik** · 10-13-2020, 01:31 AM

welp, today i had off. from work, so i decided to put that time to use (luckily the security and management didn't give me too much trouble).

So i took the wheel off, and looked to see how much the brakes are engaged. I was able to spin the wheel by hand, it wasn't easy, but not as bad as i imagined. Perhaps when the car is on, more pressure is applied to it? not sure, i didn't think of this at that time, so didn't check that hypothesis. with a few wiggles, i was able to get the caliper off.

The plan was to inspect the pistons/seals, and try to work em back and fourth. The seals looked great, id say newish, same for the pistons, they looked mint (calipers weren't even dirty). I didn't have a c-clamp, so i just used both brake pads and tried to push the pistons in with a crowbar (had the oil reservoir cap off). The first time around, pumped the brakes a bit to get them extended a bit, and although i struggled, i was able to compress them. second time around, i was not able to get them back in, only about half way. So then i figured, what do i have to loose, i might as well try and get the pistons out and inspect the inner seal. So i just pumped the brakes, hoping for both of them to pop out... well, one did, the other one didn't I started inspecting the inside seal, and it all looked perfect/newish. Now the plan was to lube it with that special brake caliper lube (red stuff i had laying around), then to put it back inside and then use wood to keep it in, while the other one pops out. For this, i loosened the bleed nipple, but... i just couldn't get the piston back in.

So at this point, i decided to take the caliper completely off. The brake fluid looked new. I tried to wiggle the second piston, tried pulling on it with wise grips (through a rag), it wouldn't budge. So then i figured i can get the other one back in, and return to plan A. First i greased it with that brake caliper lube, and i also greased the inner seal. It was tricky to get it to set, but i was able to do it, however, i was not able to push it in past just a few mm after i set it. I tried everything, i just wouldn't go. I tried adding some brake fluid inside the dust boot, but nothing. Eventually, the dust boot upper part gave up (it would come off the ring part of the piston, so i kept sliding it back up).

All this is weird. I read somewhere that some rebuilt calipers had shitty inner seal, which could make the calipers hard to slide. One other thing i didn't test was the caliper slider/or whatever it's called, the part that presses the second pad. I can't say there was a lot of grease on those, or if it was sliding smoothly. I have a suspicion that perhaps that could have caused issues as well, if it wasn't lubed right and wasn't moving smoothly, though i can't say it was bad, just not a lot of grease, just some. I also read that abs module could be busted, thus gives a bad signal.

So at this point, should i just order a new piston, or order rebuild kit and have a shop put it together? I'm not sure how much they'll want for it though, but seems pretty simple with the right tools and experience.

**CPHES** · 10-13-2020, 04:21 AM

At this point you should get another caliper. Brake failure is not a good scenario. You have an open line now? Or did you reconnect the caliper you took off? At rest, with the tire on, it should spin easily. At rest with no tire, it should turn easily using one lug bolt in, and a lug wrench for leverage. Once you ger another caliper on, a brake bleeding session is needed.

Additional thoughts - you should get a more experienced person to look at this. Taking calipers apart is not too hard. Putting them back together to be used safely needs some skills, and I’m not sure you are there yet. Now you are faced with a system that has been opened. I think you need to get a professional involved, and get this fixed right.

Also to the above. Abs looks at wheel speed differences to determine if you are in a lockup situation. Your sensors are telling the truth - the left is being slowed by the dragging caliper - abs engagement is a possible scenario.

**KinkedChrome** · 10-19-2020, 04:42 PM

Did you ever get this figured out?

**Grady in Texas** · 10-20-2020, 02:13 PM

Probably too late, but you may find the ABS sensor plug (attached to the body) has died of old age and fallen apart. Amazon has nice water tight universal 2 wire connectors that make a good replacement fitting. ~$8.00 for 4 pairs.

MUYI 5 Kit 2 Pin Way 16 AWG Waterproof Connector Wire 1.5mm Series Terminal Connector Black

**Manny G.** · 10-26-2020, 01:23 PM

One brake rotor getting too hot while normal driving sounds like the brake caliper is sticking a bit causing the friction. I would take apart the calipers and replace the piston seals, check for any dirt around them too. Definitely would be the source of odd vibrations too if the control arms and all that are good. Good luck

**Miket4991** · 10-27-2020, 02:46 AM

You need tension strut bushings.

**kotik** · 11-03-2020, 02:54 PM

sorry, here is an update:

I've contacted one of the previous owners, and he told me he replaced the brakes in February. He ordered the 750 calipers from the autozone. I read in some other bmw forums that those can be of poor quality (bad seals).

I replaced the left caliper with a Nugeon part (i read those were better quality). Since I ordered new tires before I found out about the caliper issue, i also had all 4 tires replaced (the old ones could have probably lasted another year to be honest), just to eliminate any possibility of that being an issue. During the tire replacement, i spun the wheels, and noticed that the front right had some tension. After a few days of driving, the vibration on braking came back. So i'm assuming that the front right was also locking up and warping the rotor, so i ordered right side caliper. Perhaps its a different issue all together (where it was locking up front left, then started locking up front right... i can't recall what the wheel tension was on the right wheel when i noted the left wheel tension. All i know is that left was worse than right, but don't know if right was all good or if it got worse).

However, another issue came up in the midst of all this. When i was driving on my fresh new tires, i was hit with some heavy rain. I stopped at a cafe for a bit, came out and noticed that when i press the brake pedal it makes a weird noise and stalls the car. I limped home, and did some research, which pointed to the water getting stuck in the brake booster area. This was the case, that brake booster area was quarter filled with water. I ordered a new brake booster, and just installed it today (was a bitch, cause i initially didn't know to take of the cowl, since i was following e39 m5 directions to replace it). Anyway, still in the process of putting it all back together. BTW, the rubber piece that sits at the bottom of that booster well, looked like crap/was falling apart and not allowing the water to drain, so i just cut off the part that sits on the bottom (and left the part that attaches to the firewall). I hope i didn't divide by zero there...

Could flooded booster have been an issue for a long time? probably... could this have cause some random miss-fires that i had showing up on my scanner? maybe, or maybe i need coils... Could this have caused my other brake issues? unlikely, but maybe you guys know?

Any tricks on bleeding the system at this point? I have a basic pressure bleeder, and I think i bled the brakes last time well (did it with my GF), but i did a regular bleeding procedure, not bmw specific. At this point, do i need to do a BMW specific bleeding procedure (I read about some special tools/computer/etc), or do i just bleed like normal? I prob need to bleed the clutch as well... my problem now is that the car is in my parking garage, and it would be a major pain to tow it from here (my building management is not happy with those types of things).

While on the topic of removing cowl, maybe you guys can advise. I'm missing the driver's side cabin filter assembly. Like, there is nothing there, just the master/slave and some bosch cylinder thingy. I can't figure out if that bosch thingy is from the M5, or from the 740 (I was told that abs module is from the M5 fyi). It is connected to the master cylinder. I'm not sure why i don't have the cabin filter assembly, maybe it wouldn't fit in there with that extra piece? I can't seem to find how to order it/and what i need to order.
Also, my windshield cowl is all dry rotted, so i think i'll order a new one. Ebay for $120 sounds right? or does this need to be a quality piece as well?
I noticed there are two vents there (for what seems like fresh air), the driver's side one has broken plastic tabs where it attaches (thought the plastic flap sits in its place). Should i replace the whole thing? I can't figure out how it works... I also noticed (when i opened the flap) that there is some water down there, and no drain. Is that normal?

Screen Shot 2020-11-03 at 2.51.44 PM.png

**kotik** · 11-03-2020, 03:06 PM

oh nice! thank you! Yes, i was going to ask about that. I tried to disconnect the ABS sensor and brake sensors, and the connectors just fell apart (they are still connected, but at this point to disconnect, i have to just brake them apart). So do i just cut the wires to sensors/from the car, and attach these?

- - - Updated - - -

Originally Posted by Grady in Texas

Probably too late, but you may find the ABS sensor plug (attached to the body) has died of old age and fallen apart. Amazon has nice water tight universal 2 wire connectors that make a good replacement fitting. ~$8.00 for 4 pairs.

MUYI 5 Kit 2 Pin Way 16 AWG Waterproof Connector Wire 1.5mm Series Terminal Connector Black

**KinkedChrome** · 11-05-2020, 12:25 PM

Originally Posted by kotik

sorry, here is an update:

I've contacted one of the previous owners, and he told me he replaced the brakes in February. He ordered the 750 calipers from the autozone. I read in some other bmw forums that those can be of poor quality (bad seals).

I replaced the left caliper with a Nugeon part (i read those were better quality). Since I ordered new tires before I found out about the caliper issue, i also had all 4 tires replaced (the old ones could have probably lasted another year to be honest), just to eliminate any possibility of that being an issue. During the tire replacement, i spun the wheels, and noticed that the front right had some tension. After a few days of driving, the vibration on braking came back. So i'm assuming that the front right was also locking up and warping the rotor, so i ordered right side caliper. Perhaps its a different issue all together (where it was locking up front left, then started locking up front right... i can't recall what the wheel tension was on the right wheel when i noted the left wheel tension. All i know is that left was worse than right, but don't know if right was all good or if it got worse).

So you put new calipers on the car, the problem went away for a little bit and then came back?

Originally Posted by kotik

However, another issue came up in the midst of all this. When i was driving on my fresh new tires, i was hit with some heavy rain. I stopped at a cafe for a bit, came out and noticed that when i press the brake pedal it makes a weird noise and stalls the car. I limped home, and did some research, which pointed to the water getting stuck in the brake booster area. This was the case, that brake booster area was quarter filled with water. I ordered a new brake booster, and just installed it today (was a bitch, cause i initially didn't know to take of the cowl, since i was following e39 m5 directions to replace it). Anyway, still in the process of putting it all back together. BTW, the rubber piece that sits at the bottom of that booster well, looked like crap/was falling apart and not allowing the water to drain, so i just cut off the part that sits on the bottom (and left the part that attaches to the firewall). I hope i didn't divide by zero there...

Could flooded booster have been an issue for a long time? probably... could this have cause some random miss-fires that i had showing up on my scanner? maybe, or maybe i need coils... Could this have caused my other brake issues? unlikely, but maybe you guys know?

As I recall from the auction pictures, it looked like this car was missing the filters and filter covers that go in the hood. The covers help to drain the water in the correct location. However not uncommon for the drain to get clogged, especially with the filter covers missing. I would get that fixed right away.

I doubt the flooded booster had anything to do with the brake problem, but not impossible I suppose. I do think it could be related to your misfire issue though. On my S62 swap, the brake booster line was rock hard, cracking and crumbling. Most of it is hidden by the intake manifold, it is worth pulling off to inspect it though.

Originally Posted by kotik

Any tricks on bleeding the system at this point? I have a basic pressure bleeder, and I think i bled the brakes last time well (did it with my GF), but i did a regular bleeding procedure, not bmw specific. At this point, do i need to do a BMW specific bleeding procedure (I read about some special tools/computer/etc), or do i just bleed like normal? I prob need to bleed the clutch as well... my problem now is that the car is in my parking garage, and it would be a major pain to tow it from here (my building management is not happy with those types of things).

If you didn't let it lose a lot of fluid, its probably fine to bleed as normal. If the pedal doesn't feel firm and correct, at that point I'd get a way to cycle the ABS and bleed it better.

Originally Posted by kotik

While on the topic of removing cowl, maybe you guys can advise. I'm missing the driver's side cabin filter assembly. Like, there is nothing there, just the master/slave and some bosch cylinder thingy. I can't figure out if that bosch thingy is from the M5, or from the 740 (I was told that abs module is from the M5 fyi). It is connected to the master cylinder. I'm not sure why i don't have the cabin filter assembly, maybe it wouldn't fit in there with that extra piece? I can't seem to find how to order it/and what i need to order.
Also, my windshield cowl is all dry rotted, so i think i'll order a new one. Ebay for $120 sounds right? or does this need to be a quality piece as well?
I noticed there are two vents there (for what seems like fresh air), the driver's side one has broken plastic tabs where it attaches (thought the plastic flap sits in its place). Should i replace the whole thing? I can't figure out how it works... I also noticed (when i opened the flap) that there is some water down there, and no drain. Is that normal?

That is all stock E38 stuff shown in the picture. As mentioned above, there are cabin filters are in the hood. Another set of filters are inside the car, but that is irrelevant to this discussion. The box on the pass side that your seeing contains the ECU, relays, fuses, etc. $120 sounds right for that part, I think new OEM parts were over $300 last I checked.

**Manny G.** · 11-05-2020, 12:51 PM

Originally Posted by kotik

sorry, here is an update:

I've contacted one of the previous owners, and he told me he replaced the brakes in February. He ordered the 750 calipers from the autozone. I read in some other bmw forums that those can be of poor quality (bad seals).

I replaced the left caliper with a Nugeon part (i read those were better quality). Since I ordered new tires before I found out about the caliper issue, i also had all 4 tires replaced (the old ones could have probably lasted another year to be honest), just to eliminate any possibility of that being an issue. During the tire replacement, i spun the wheels, and noticed that the front right had some tension. After a few days of driving, the vibration on braking came back. So i'm assuming that the front right was also locking up and warping the rotor, so i ordered right side caliper. Perhaps its a different issue all together (where it was locking up front left, then started locking up front right... i can't recall what the wheel tension was on the right wheel when i noted the left wheel tension. All i know is that left was worse than right, but don't know if right was all good or if it got worse).

However, another issue came up in the midst of all this. When i was driving on my fresh new tires, i was hit with some heavy rain. I stopped at a cafe for a bit, came out and noticed that when i press the brake pedal it makes a weird noise and stalls the car. I limped home, and did some research, which pointed to the water getting stuck in the brake booster area. This was the case, that brake booster area was quarter filled with water. I ordered a new brake booster, and just installed it today (was a bitch, cause i initially didn't know to take of the cowl, since i was following e39 m5 directions to replace it). Anyway, still in the process of putting it all back together. BTW, the rubber piece that sits at the bottom of that booster well, looked like crap/was falling apart and not allowing the water to drain, so i just cut off the part that sits on the bottom (and left the part that attaches to the firewall). I hope i didn't divide by zero there...

Could flooded booster have been an issue for a long time? probably... could this have cause some random miss-fires that i had showing up on my scanner? maybe, or maybe i need coils... Could this have caused my other brake issues? unlikely, but maybe you guys know?

Any tricks on bleeding the system at this point? I have a basic pressure bleeder, and I think i bled the brakes last time well (did it with my GF), but i did a regular bleeding procedure, not bmw specific. At this point, do i need to do a BMW specific bleeding procedure (I read about some special tools/computer/etc), or do i just bleed like normal? I prob need to bleed the clutch as well... my problem now is that the car is in my parking garage, and it would be a major pain to tow it from here (my building management is not happy with those types of things).

While on the topic of removing cowl, maybe you guys can advise. I'm missing the driver's side cabin filter assembly. Like, there is nothing there, just the master/slave and some bosch cylinder thingy. I can't figure out if that bosch thingy is from the M5, or from the 740 (I was told that abs module is from the M5 fyi). It is connected to the master cylinder. I'm not sure why i don't have the cabin filter assembly, maybe it wouldn't fit in there with that extra piece? I can't seem to find how to order it/and what i need to order.
Also, my windshield cowl is all dry rotted, so i think i'll order a new one. Ebay for $120 sounds right? or does this need to be a quality piece as well?
I noticed there are two vents there (for what seems like fresh air), the driver's side one has broken plastic tabs where it attaches (thought the plastic flap sits in its place). Should i replace the whole thing? I can't figure out how it works... I also noticed (when i opened the flap) that there is some water down there, and no drain. Is that normal?

Screen Shot 2020-11-03 at 2.51.44 PM.png

No its not normal to see water collecting here... you have a drain clogged somewhere.

Also the area on the driver side doesnt have a cover, its an open cubby with the DSC pump and brake reservoir and brake booster. The cabin filter on the E38 is attached to the hood as compared to the E39 which uses these cubby areas for cabin filters. The way the vents work is when the hood is closed, the flaps are pushed open to allow the air that comes in through the hood vents through the cabin filters and down through the opened flaps. When the hood is opened, those flaps should be closed.

**CPHES** · 11-05-2020, 07:40 PM

Bleeding. I just went thru a similar issue. Mini Cooper with a rusted thru hard line. Bleeding is the same for all cars - start at the right rear, then left rear, then right front, last left front. Bleeding the line furthest from the master first. A LOT of air came out of my left front, ( the bad line was left rear ). Test the pedal carefully before going anywhere. Anyone else want to chime in, please do.