Clutch Master Cylinder Replacement & Creaky Pedal Fix DIY

[BimmerM3inGA]

I’ve been noticing lately that the clutch in my 1998 M3 with 108K miles seems to be engaging very early in the pedal travel. As soon as I lift the pedal off the floor, the clutch starts to “grab”. As a consequence, I have to push the pedal all the way to the floor to get it to disengage. Not only is it annoying, but it makes the car very difficult to drive smoothly. There could be more than one cause for this problem. The first, and easiest to fix, would be the need to flush the hydraulic fluid (there could possibly be air in the system). Second, the master or slave cylinder could be faulty. Third, the clutch could be in need of replacement.

The hydraulic clutch system is a relatively simple affair. A line runs from the brake fluid reservoir to a master cylinder attached to the clutch pedal. When the clutch pedal is pressed, a piston inside the master cylinder forces brake fluid through a second line to the slave cylinder. The slave cylinder is attached to the outside of the transmission, just behind the bell housing. It has a piston inside the pushes on a short rod (or “plunger”) that, in turn, presses on the clutch release lever. A spring attached to the clutch pedal returns the pedal to its neutral position and releases the pressure from the master and slave cylinders.

I already bled the lines and checked the slave cylinder, and checking the clutch itself is a major (and expensive) job. So replacing the master cylinder is the next logical step in trying to resolve this problem. After replacing the cylinder, the clutch feel is better, but still not how I want it. At nearly 110K miles, it’s probably time for a new clutch anyway. And that’s probably what it’s going to take to restore normal clutch feel.

Like every other E36 car that I’ve driven, the clutch pedal creaks constantly. Since I’d be doing 90% of the work involved in fixing the creak, I decided to take care of that at the same time. I’ll also cover that procedure, so you can just tackle that portion if that’s all you’re interested in.

This particular job isn’t all that difficult, but access is a challenge. There were some choice curse words directed toward some clutch components during this procedure! You have to contort yourself into the footwell while looking up into the dashboard – not easy to do! There were many times when I couldn’t see what I was doing and work at the same time. So I had to take a good look, and then work by feel. If you have access to a lift, it may help.


This is what the master cylinder looks like.

So, first things first: If you have a Bentley manual, leave it on the shelf for this job. The procedure outlined in the manual is not only flat out wrong, but it’s impossible. It must’ve been written for a different model. With the exception of bleeding the system after you’re done, the entire job is performed from within the passenger compartment – not from inside the engine bay as described in the Bentley manual. I also must apologize in advance for the lack of good photos. It was extremely difficult to get photos as I worked. I did the best I could, but it was either too dark, or there were too many obstructions for the camera to focus. Plus, it’s kind of a cheap camera, so that probably didn’t help!

The first thing I would advise would be to pop the hood, and use a suction pump or turkey baster to get as much brake fluid as possible out of the reservoir. Once you disconnect the fluid inlet to the master cylinder, any fluid “above” it in the system will drain out. So the more you remove now, the less you’ll have to clean up later.

Next, remove the lower dash panel on the driver side. It is held on by two screws below the instrument cluster and one along the edge next to the center console. Disconnect the wire for the footwell light and door chime. The edge of the panel near the firewall fits into slots. Make a note of them so you can reinstall it in the proper position.

If you look up into the dashboard, you can see the clutch apparatus. The clutch pedal assembly is a single piece of molded plastic that pivots on a pin about a foot directly above the actual pedal (this is where the creaking comes from). The master cylinder attaches to the pedal about midway up, and the master cylinder is attached to the car with two bolts. The master cylinder attaches to the clutch pedal with a pin and clip. Remove the clip by grabbing the end with needle nose pliers and twisting slightly as you pull. With the clip off, push out the pin. The clutch return spring is attached to the clutch pedal with another pin, but is just seated into a notch at the other end. It will fall out when you pull the pin for the master cylinder. As I took everything apart, I cleaned and greased every moving part.


The master cylinder is held in place by two bolts and the inlet and outlet line fittings. Pay attention to the position of all the bits so you can reassemble it later.

To ease access to the master cylinder (and to address the creaky pedal) it’s necessary to remove the pedal assembly. You’ve already done 90% of the work at this point, so you might as well take the extra couple of steps. The assembly is held on the pivot pin by a clip identical to the one for the pin in the master cylinder. Remove it in the same fashion and slide the assembly off the pin.


These clips hold the clutch pedal assembly and master cylinder rod in place. They are easy to remove - once you figure them out.

Thoroughly clean all the nasty dried grease from the pin and bushings and slather on fresh grease. There are two bushings on the pedal. Both of mine had slits in them, but I’m not sure if they are supposed to be there. I didn’t want to wait for new parts if they were, in fact, not supposed to have slits. So I just reassembled it using the old parts. It would probably be a good idea to order new bushings and have them on hand when you do the job. I used a white lithium grease because I didn’t want to take a chance of the grease attacking the plastic bushing or pedal assembly. I’m not saying that’s only product to use, but it seemed like the best choice for me. Set the cleaned and greased pedal assembly aside.


This is where the clutch pedal pivots (and creaks). Clean thoroughly and grease before you put it back together.

Next remove the two bolts securing the cylinder. The lower bolt threads into a nut, while the upper bolt threads into the bracket that hold the brake and clutch pedal switches. Pay attention to the orientation of the bracket or you’ll tear your hair out trying to figure out how it goes back in (ask me how I know!).


This is the same photo as above, but I wanted to show the mounting bolts again.

Now it’s time to get dirty. Place a disposable plastic bowl under the master cylinder to catch the brake fluid that drains out, and put several layers of paper in the floorboard to catch any fluid that spills out of the dish. Keep some paper towels on hand as well. If your fluid hasn’t been flushed in a while and it gets on the carpet, it will stain it (again, ask me how I know).

The two fluid lines are held in place by small metal clips. There are very easy to remove and install. When you are holding the cylinder in your hand. Up under the dash with limited access, it’s a different story. So it’s a good idea to practice a few times with the new cylinder to see how the clips work and the best way to release them. There is a flat spot where a flat-blade screwdriver can easily slip under the clip. But it’s not easy to access on the installed part. So some practice will definitely help. When you’re ready, release the clip for the outlet line first (bottom fitting). Try to let as much fluid as possible drain out. When it’s finished draining, twist the cylinder around to gain access to the clip for the inlet line and release it. More fluid will drain out and run down your arm. Why does brake fluid feel hot when it touches your skin? These parts are plastic, so use care when handling them.


These little metal clips hold the inlet and outlet lines in place. They are easy to remove once you learn how to release them - but it's not obvious with your head twisted around under the dash - so practice on the new one first.

Once the old cylinder is out, install the new one in reverse order. If you paid attention to the various bolt and bracket locations, reassembly shouldn’t present too much of a challenge – except for the return spring. The top end must be properly seated in its notch and it’s tough to compress the spring by hand and force it into place. But it can be done with a little determination and patience. Remember to grease everything that moves!


I couldn't get a photo of the upper perch for the clutch return spring, so my illustration will have to suffice. The red portion is the end of the return spring and the gray portion is the metal bracket into which it fits. The lower end of the spring attaches to the clutch pedal with a pin and clip, but he upper end just sits in this perch. The spring must be compressed by hand and put in place after the clutch pedal and master cylinder are in place. It takes some force and cussing, but can be done.


Once the cylinder is installed, it’s time to refill and bleed the system. If you don’t have a pressure bleeder, I highly recommend adding one to your parts order. It’s well worth the $55 asking price. Since you drained most (if not all) of the fluid from the reservoir, you must bleed the brakes as well as the clutch. I’ll give a quick rundown of the brake bleeding procedure, but won’t go into a lot of detail since there’s plenty of info out there about it already. Start by attaching your pressure bleeder to the reservoir and filling the bleeder with your favorite DOT 4 brake fluid (I like Valvoline SYN Power). Pump up the pressure bleeder to 20 PSI and remove the right rear wheel. Open the bleeder valve until clear, bubble-free fluid flows out. Next is the left rear, then right front, pumping up the bleeder in between each. The left front is last, but leave the wheel off after you finish bleeding. The last thing to bleed is the clutch, and you can’t get to the bleeder with the wheel on (unless you are using a lift – then it won’t matter). The slave cylinder has the bleeder valve on it, and it’s just like the bleeder for the brakes. Crack it open with a 7mm wrench and wait for the bubbles and old fluid to drain out. If you aren’t using a pressure bleeder, have a helper CAREFULLY press the clutch while you open the bleeder. With the pedal on the floor, close the bleeder, then release the pedal. Repeat until there are no more bubbles. To thoroughly bleed the clutch when not using a pressure bleeder, it’s best to remove the slave from the transmission and rotate it until the bleeder if pointing up. Then bleed it again – this ensures that no air remains in the lines. But BE CAREFUL – DO NOT press the clutch without pressure on the end of the plunger. Hold it in your hands and keep the plunger pressed in. If you don’t, the internal piston will pop out and you’ll have to replace the slave cylinder. This is why it’s highly recommended to use a pressure bleeder! When satisfied that all air is out of the system, reinstall the slave cylinder and put the wheel back on.

Put the cap back on the reservoir and you’re done. Now go wash the brake fluid out of your hair and have a cold one. You’ve earned it!

[NY98M3]

Great write up!

[Mtastic]

Jeez you are just the write up king. Just did my cooling system now it looks like I'll be using this! Thanks!

[BimmerM3inGA]

As this car ages, I seem to be spending more and more time under it. So I figure that I might as well treat my repair experiences as an opportunity to contribute to this community.

I've benefited from other people's work and effort to write DIY's, so now I'm just trying to return the favor. Maybe if I do enough of them, Karma will take pity on me when it's time to replace the clutch!

[NeilM]

Nice write-up, but alas by reusing the orginal clutch pivot bushings you've bought yourself a return ticket to one aspect of the job. Regreasing them simply won't help for long. The longer term fix is to buy upgraded plastic bushings from UUC, about $20.

Neil
96 M3

[mball19]

Did changing the clutch master cylinder make your clutch engage higher? Does anyone know if it is possible to install a speed bleeder on the slave cylinder?

[BimmerM3inGA]

NeilM: Thanks! And, I know. I didn't realize that I might need new bushings when I started the job, and wasn't in a position where I could order (and wait for) parts. I had to go with what I had in hand. If/when it starts creaking again, it'll be easier to replace them since I know how to do it now.

mball19: A little. It didn't totally fix the problem, but it did make a noticeable improvement. The bleeder on the slave is the same type as on the brakes. So as long as there's room, I don't see why a speed bleeder wouldn't work.

[CRYPTiC]

Good write-up! Yours are definitely more extensive than mine.

[dcvee]

Great write up...and I couldn't agree with you more. The bentley manual was a BIG dissapointment for me so far. I've owned 2 other bentley manuals for other cars and they've been great. Seems like the one for the E36 sucks.

Don

[BimmerM3inGA]

Not to get off topic, but considering how people extoll the virtues of the Bentley manuals, I rushed out and bought one the first time I needed to work on my car. Honestly, it isn't any better than the Chilton's manual I got at Autozone for 20 bucks.

My wife had an E46 323i and I considered gettting a Bently after the warranty exprired, but that sucker is 100 bucks! And since the E36 version was so disappointing, I decided to pass it up.

[jszy25]

Wow - I am so happy I found this thread. I am waiting to receive my master cylinder in the mail and then I will be doing the install.

This is a great write-up and I am now very confident I can knock this out. My only problem is that I don't have a bleeder, but now I am thinking about buying one for this job and feature brake jobs.

Where did you buy your bleeder?

thanks again.

[BimmerM3inGA]

You definitely want a bleeder. It will make your life so much easier! I got mine from Bavarian Autosport, but just about all the top vendors carry them.

[jszy25]

Cool - thanks.

I am definitely going to buy one....I am trying to find out if I can buy one from a local place before I resort to buying one online and waiting for shipping.

[BimmerM3inGA]

The problem with buying one at the local parts store is getting the proper cap that fits the fluid reservoir. You'd probably have to jury rig it to make it fit your BMW.

[IppoJ]

Does anyone know if it is possible to install a speed bleeder on the slave cylinder?

I think there is a bleeder screw on one side of the transmission... or I'm thinking of something else.

[jszy25]

The problem with buying one at the local parts store is getting the proper cap that fits the fluid reservoir. You'd probably have to jury rig it to make it fit your BMW.

I just went and ordered the Motiv bleeder so hopefully I will have it in a day or two. I didn't want to mess around trying to find a local one to fit.

[BimmerM3inGA]

You have chosen wisely!

[jszy25]

You have chosen wisely!

Quick question:

I was just reading how you bleed your system after you swapped out the master cylinder.

My question is....does the power bleeder get fluid through the new master cylinder or do you have to pump the clutch manually to get it started?

[BimmerM3inGA]

It'll suck it right through. It would help to pump it (slowly) a few times, though. Just to be sure there's no air trapped in the system.

[Balthazarr]

This should be in the 3-series FAQ.
Definitely, one of the better diy's .

See about getting on bimmerdiy.com, too.

[BimmerM3inGA]

This should be in the 3-series FAQ.
Definitely, one of the better diy's .

See about getting on bimmerdiy.com, too.

Thanks! How would one go about doing that?

[jszy25]

It'll suck it right through. It would help to pump it (slowly) a few times, though. Just to be sure there's no air trapped in the system.

Got it...thanks for your help.

[Balthazarr]

Thanks! How would one go about doing that?

Actually, there is a diy sub-forum.
This is something I haven't noticed before since I'm rarely in that area.

Just start a new thread.
DIY forum

[JETninja]

Actually, those of you (including the OP) bashing the Bentley are incorrect, partially. In fact the Bently is correct for earlier cars like my '95 M3 (10/94 build date) and my Clutch Master Cylinder is a much longer piece then yours shown above, it actually passes through the Firewall to the Slave Hard Line. (like in the Bentley and on Real OEM) I don't know when they went to the easier to replace part like yours. (I think in '97 model year, RealOEM wasn't much help)



I'm in the middle of mine, only have the two lines left to remove, trying to see if there is enough play to pull the Hardline into the footwell and remove the fitting there. (much preferable to doing it from under the car if possible!) If you have to do it from under the car, then you have to re-bolt the Master so you have something to turn against. Maybe (no promises) I can add some pics for the earlier (and much nicer except in this area! ) car owners.....Mods, this thread really should be in the DIY subforum as there are none on this subject in there.

Edit; Having a real tough time. On these earlier cars, the Supply tube has a Plastic Nipple that plugs into the top of the MC. Since your blind and no room, I can't get anything under the lip, and while I can pull the MC down quite a bit, so far it aint budging and I'm afraid I'll damage the Top Resivoir. On top of that, I see no way I can get to the Slave hardline from outside the firewall. I can see it from on top but there are abs lines, electical lines, Fuse box, brake booster, etc all in the way leaving no room to get even a skinny hand like mine in there. From underneath you can't even see it, there is a body shelf blocking any view. There does seem to be a fair amount of play, so I may be able to pull enough into the footwell, if I can ever get the supply line yanked out! Tell ya what, this is one of those jobs that it may be worth the few hundred $$ having a shop do it!

Edit #2;

Ok, got the bastage out! I kept yanking and got the Feed Tube to come off. Then I was able to pull the MC forwad (towards me) just enough to get the Slave line through the Firewall, and get a 11mm Flare wrench on the Hardline. Problem though, no travel to turn it much and I could not re-bolt the MC since it was now a couple inches forward. Vise Grips to the rescue! Using a really old Vice Grip wrench on the MC Body, and while holding the Flare Wrench in place, was able to rotate the MC and get it loosened and then off.

The next pain was getting the Input plasic nipple off, forget it. It got squished a bit in the process, neighbor already had an aftermarket white one. (has longer neck too..hmmm) Getting the new nipple was just as much of an adventure! Lube with brake fluid and keep working it so the rubber bushing/seal rides up it and gives the proper seal. About to try getting the new MC in place, back in a bit!

Edit #3

Got the MC fitted and tightened (same flare wrench / vise grip combo) but even with pulling, the fill tube is just to short. I imagine at the factory they attach it first and tighter the slave side on the firewall, I couldn't do that. So, tomorrow I'm picking at up from Napa 6' 1/4" of silicon tubing (5/16's is better, but they cant get that. Autozone & Kragen were no help at all!) and since it's not under pressure I will either splice or replace the entire line, leaving a few spare inches so I'll never have to struggle with this again! Getting the end off the Master Reservoir with out breaking it seems like a challenge too.... At Least it was darn easy to change my Brake Light Switch finally!

[BimmerM3inGA]

OP here: I stand corrected and my apologies to Bentley. I've noticed that there are lots of inconsistencies in the E36 manual and that must be due to changes made to the cars during production. I just wish the manuals could reference that somehow, so I'm not scratching my head wondering why my car doesn't look like the one in the picture.

Anyway, it looks like quite an ordeal swapping out the clutch MC on earlier production cars. I'm glad mine was so much easier! When I was trying to figure out how to do the job, I thought to myself what a biatch it would be to try to do it from inside the engine bay. Looks like I was right!