Looking for insight: brake pad wear, head gasket leak and high idle

[nadodude]

Hey everyone - thanks in advance for reading this long post. I’m concerned about a few issues I’m noticing with my new-to-me car. Am hoping you all can give insight into each issue so I can set my expectations and look for solutions. Car is a 1991 325i Convertible (late model). Everything is bone stock.

1. Brakes - The brakes in my car are awful and tend to wear quickly. I have to push the brake pedal with lots of force to slow and stop the car. I do not feel safe. I remember the brakes on my previous 1992 325i convertible feeling nimble, responsive and quick. Also, the car has 158,000 and the brakes have been replaced 14 times throughout its life according to the records I have. The brakes on every car I’ve owned have lasted me at least 50k miles so this car is eating through pads and rotors. Is this history normal?
   
   1. Feb. 1993 - 22,748
      
      • Front and rear pads
      
      
   2. Aug. 1994 - 33,638
      
      • Front and rear pads
      
      
   3. March 1996 - 44,172
      
      • Front and rear pads
      
      
   4. April 1997 - 50,021
      
      • Rear pads and rotors
      
      
   5. December 1997 - 54,691
      
      • Front pads
      
      
   6. Feb. 2003 - 83,138
      
      • Front pads and rotors
      
      
   7. July 2003 - 86,150
      
      • Rear pads and rotors
      
      
   8. Feb 2006 - 92,980
      
      • Front pads
      
      
   9. July 2009 - 102,342
      
      • Front and rear pads & rotors
      
      
   10. Nov. 2011 - 114,715
       
       • Front and rear pads and rotors
       
       
   11. Oct. 2013 - 117,241
       
       • Rear pads and rotors
       
       
   12. January 2017 - 126,315
       
       • Front and rear pads and rotors
       
       
   13. Aug 2020 - 135,759
       
       • Front pads and rotors
       
       
   14. May 2022 - 152,835
       
       • Rear pads and rotors

I bought the car a month ago with 157k miles and had a pre-purchase inspection done. The mechanic said the front pads were at 50%. I've put about 2k miles on it in the month I’ve had it and now the brake lining light is on. Does it seem reasonable for the front pads to wear down with just 2k miles?

2. Head gasket leaking oil

• BMW of San Francisco replaced the head gasket in Oct. 1996 (48,072 miles) and July 2005 (92,218 miles). Head gasket is leaking like crazy again. This isn’t normal for e30s to be leaking this bad after having the engine rebuilt twice. Annoyed.

3. High idle - car idles really high when in park - around 1500 RPMs but then drops to about 800 when put in drive. Car does not run rough, but it does eat fuel like crazy and seems a bit sluggish. I am getting about 200 miles to the tank - using the odometer against a full tank. Any ideas as to what’s causing this and what to replace to fix the issue?

Let me know if I can elaborate and provide more details to clarify. I appreciate all your help.

Thanks

[82eye]

1. start by bleeding the brakes. if that doesn't work go through and refresh the braking system. by this point is probably needs hoses and maybe even hard lines. check the MC, may need to replace it.

2. it isn't the head gasket. it'll be the cam seal or something else. where you see it pooling is not where it is coming from.

3. could be lots of things but sounds like you have vacuum leaks. smoke test the car and replace any old or worn rubber under the hood.

[nadodude]

Thank you for the suggestions. Time to look up the DIYs.

[PEZ2]

Your brake use out paces my 4 e30s combined, although there seems to be pattern to the early change schedule as if by design. If all pads are worn equally most likely your master cylinder is “sticking” and needs to be replaced and system flushed. It can also explain lack of stopping power. When the brake system is operating at full pressure other conditions may develop like leaking rubber lines or frozen/ slow calipers. Heat gun rotors to look for differences and address as needed. Your fuel economy can be a function of your brake system if drag is excessive.

[nadodude]

Thank you. I’ve ordered a new set of brake pads and the master cylinder. Will also do a brake flush. It is absolutely wild that BMW or the original owner never expressed concern for the early change schedule. Something was obviously not right yet no one said anything. Also, the owner had BMW of SF replace the driver door lock and a rekey like 5 times because it kept breaking - that many replacements seems suspicious.

[aaverhulst]

Follow Pez2's advice. Your brakes must be dragging. They will get hot and decrease their stopping power. I'm on my second set at 225,000. Find your oil leak and vacuum leak. You are correct, get in your DIY mode. I suggest not taking to a BMW dealer as their E30 mechanics are long gone.

[tomstin]

Were the brake calipers ever replaced or rebuilt? If not, those are probably the problem. They are dragging and wearing out the pads and with heat in them, probably causing the soft pedal. If you plan on keeping and driving the car, I would rebuild / replace the master, brake hoses, calipers, pads and rotors. And blow out the brake hard lines when you have everything apart.

[nadodude]

Thanks guys. The pedal is not soft. It’s extremely hard. It will depress but slowly and it’s just hard and not sensitive. I have to plan a long slow down and stop between me and the car in front of me. Not sure if that helps narrow down the issue. Brakes have been wearing rapidly since the car was new as you can see from the brake schedule, so if you think the calipers are the problem, then they needed to be repaired or replaced when the car was new.

From research, it seems hard brake pedals are a symptom of a bad brake booster, and soft pedals that fall to the floor are due to failing master cylinders. Though the car is burning thru pads and rotors meaning the master cylinder is stuck open. Maybe it’s both?

I discovered today the car has an awful intake leak under the exhaust manifold. You can hear the suction loudly. I wonder if that is causing the hard braking issue due to lack of vacuum and the poor gas mileage and high idle…

[82eye]

go have a look at the e30 convertible top gear episode. the brakes on at least 2 of those cars were fucked too. one had concrete slabs in the trunk that the owner thought would help slow it lol

best thing you can do is check / rebuild the calipers / master / and get some stainless lines.

[nadodude]

Hey 82eye, question about the cam seal - I purchased the timing belt kit below and had a mechanic replace all the parts. It includes two cam seals - are these the ones you suggested needed replacing?

https://www.fcpeuro.com/products/bmw...x-325i-e30kit1

Thank you,

[82eye]

Hey 82eye, question about the cam seal - I purchased the timing belt kit below and had a mechanic replace all the parts. It includes two cam seals - are these the ones you suggested needed replacing?

https://www.fcpeuro.com/products/bmw...x-325i-e30kit1

Thank you,

one of those are for the crank, but yes, the cam seal should get refreshed during the timing belt / water pump / tensioner replacement interval.

the cam seal is notorious for leaking and can be hard to figure out. i'd replace the valve cover gasket at the same time. likely your oil leak is one or the other.

edit : fyi - on the brakes - worn e30 soft brake lines are known to internally collapse with time, resulting in locking and dragging brakes, leading to excessive wear.

- - - Updated - - -

Hey 82eye, question about the cam seal - I purchased the timing belt kit below and had a mechanic replace all the parts.

you'll need to learn how to do this stuff yourself if you hope to afford driving this car.

[nadodude]

So what’s really interesting is that the car idles perfectly after the timing belt change. 750 RPM whether in park or drive. The intake leak is still there though as I can hear the loud suction sound. I think I can check the high idle issue off my list? And I’m guessing the poor fuel mileage is due to the vacuum leak. Will try to get that fixed in the next week.

For the oil leak, I changed the cam seal during the timing belt swap, so I’ll monitor and see if the leak is still there. If I’m lucky then I can check that off the list too.

Focusing on breaks this weekend…more to come!

[nadodude]

just replaced the master cylinder with a new one, did a brake bleed and put new pads all around. Massive improvement. The brakes feel sensitive and the peddle is squishier and moves according to the speed. It feels right. Though it still doesn’t stop entirely on a dime. The mechanic said he thinks the booster isn’t working at its full capacity as he saw it shaking when he was testing the system. I told him about the big intake leak and we think getting that fixed will close the system and make the booster a bit more powerful. He said the calipers looked great. I’ll report back this week when I get the intake leak fixed.

What’s annoying is now the brake lining light is on after the brake service and we replaced the sensors. Any ideas why it’s illuminating?

[82eye]

just replaced the master cylinder with a new one, did a brake bleed and put new pads all around. Massive improvement. The brakes feel sensitive and the peddle is squishier and moves according to the speed. It feels right. Though it still doesn’t stop entirely on a dime. The mechanic said he thinks the booster isn’t working at its full capacity as he saw it shaking when he was testing the system. I told him about the big intake leak and we think getting that fixed will close the system and make the booster a bit more powerful. He said the calipers looked great. I’ll report back this week when I get the intake leak fixed.

What’s annoying is now the brake lining light is on after the brake service and we replaced the sensors. Any ideas why it’s illuminating?

did the replacement pads have a sensor ? if not it's the brake wear sensor. the common defeat was to cut the pigtail and splice the two wires together.

[nadodude]

Yep, bought new sensors (front and rear) for the new pads. I’m thinking it’s the SI board The brake lining light was flickering on and off before replacing the pads and sensors.

[82eye]

Yep, bought new sensors (front and rear) for the new pads. I’m thinking it’s the SI board The brake lining light was flickering on and off before replacing the pads and sensors.

you'd have tach issues and other stuff going on. could be your pads need to bed in is all.

[aaverhulst]

Yep, bought new sensors (front and rear) for the new pads. I’m thinking it’s the SI board The brake lining light was flickering on and off before replacing the pads and sensors.

I put a piece of black tape over the light. To me it's not worth playing around trying to fix it.

[Mikealwa]

That's how I fixed a check engine light on my X5, works great 🙂

[nadodude]

Update:

- vacuum leak fixed. The intake gaskets were basically non-existent. Car feels peppier and much quieter. Super exciting repair. Brakes feel even better too. Big improvement in gas mileage too. While the car didn’t run rough before, it felt sluggish and as if it were suffocating, so I’d have to floor it to get it to move. Gas pedal is much more sensitive.

- replaced the front brake pad sensor with a new one and the light is off now. The male pin in the first new one was super recessed and wasn’t meeting the female plug from the car.

All in all these were much simpler repairs than anticipated! Thanks for helping out!

Now time to wash, drive and take pics of it so y’all can see the finished product!