Brakes stuck on

[Peace_Power]

Hello,

I recently bought an E30 Touring 325i -89. It has been sitting unused for a while and has a lot of issues but I am determined to bring it back to life. (=

The worst issue it is that it feels like the brakes are on. I can hear a noise as the wheels turn from the rear that get quicker when I speed up.

It takes a lot of throttle to get it it up to speed and when I let off the throttle it comes to a stop quicker than it should.

But when lifted off the ground though I can turn all the wheels without too much trouble..

First I took the calipers off and cleaned them and made sure the sliding bolts got some grease. And I noticed uneven brake pad wear on both sets of pads in the rear.

I then thought the sound was a bad wheel bearing, so I changed 'em in the rear and they were probably due but didn't look too bad. But the sound continues.


So is a rebuild off the rear callipers next?

[TimeMachinE30]

I would rebuild them. Easy enough. And after sitting for a while, doing a once over on the brakes is a sound idea. Flush the fluid, inspect brake hoses... you may have a seized/sticking piston?

[Peace_Power]

I would rebuild them. Easy enough. And after sitting for a while, doing a once over on the brakes is a sound idea. Flush the fluid, inspect brake hoses... you may have a seized/sticking piston?

I really hate working on brakes, and in my experience a rebuild doesn't last very long anyway. The rusted pistons needs changing and a rebuild kit doesn't include them.

I think I might just get new callipers for the rear, they're not too expensive and will last a long time.

Fuel lines and brake lines are all shit so I might need all new lines under the car. This is turning into an expensive restoration. =(

[cunninglinguist]

Some places sell stainless caliper pistons, if rust will be a problem.

http://aakmotorsports.com/stainless-steel-brake-caliper-pistons.aspx

[TimeMachinE30]

Brass guide pins from BavAuto.

Would make for an expensive.. and tricked out caliper.

[Peace_Power]

I just ordered new stuff. I can't be bothered to rebuild another brake caliper =(

So some new Brembo disks and pads with new callipers are going on there. (=

I'm so looking forward to get a proper test drive out of this m20b25 engine! =P

[TimeMachinE30]

I'm rebuilding and restoring a full set of brakes currently. Cannot see why they wouldn't last for another 25 years and 150k.

[Peace_Power]

I'm rebuilding and restoring a full set of brakes currently. Cannot see why they wouldn't last for another 25 years and 150k.

Well I am jumping to conclusions here of course but I am assuming that the piston itself is seized b/c of oxidation. The rust leaves nasty imperfections in the surface of the piston which the new rubber seal from a rebuild rubs against. That internal seal will wear out pretty quick if the piston isn't smooth.

A rebuild kit from my local vendor is about 50 bucks and a brand new entire calliper 150.

There's the 100 bucks difference and I know the smart choice would be to rebuild but I rather pay more for the peace of mind.

[Peace_Power]

So I got my hands on a completely restored set of brake callipers and got the old ones off the car.

The old ones were difficult to get apart, compressed air wouldn't do it. =/

Inside the seals all looked good and the pistons were in pretty decent shape.

There was some residue/thick gunk and little particles in the bottom inside of the calliper. I bet that was the problem.


I guess the brakes hadn't been flushed in quite a while and the fluid was bad. =/

[Peace_Power]

The damn brakes are still sticking! Argh!


So the new rear callipers did little. =/

It's like all 4 callipers are slightly sticking. And when driving the steering wheel doesn't pull to one side or the other.

You can turn all four wheels by hand and it's not too hard but it's not "free" either.

I tried flushing the system and got maybe half a litre out (need to buy more new brake fluid) but apart from the odd tiny black particle the fluid looked good coming out.

I'm unsure what the problem is, but I'm guessing the master cylinder, bad brake line, brake booster needing adjusting, or some other thing. =/

Any ideas?

[AndrewBird]

Have you inspected the rear parking brake components? They could be what is sticking or out of adjustment.

[Peace_Power]

Have you inspected the rear parking brake components? They could be what is sticking or out of adjustment.

Yeah, I had a look at the parking brakes and they don't appear to have been sticking. There's lots of material left on 'em too.

And it doesn't look like anyone has been messing with the MC or brake booster so I bet those are all original. And not a mismatch.

There's quite a bit of new brake lines though put on by PO.

And I noticed today that it indeed does pull to one side, the right. =/

[Peace_Power]

So today I finally had some progress.

I figured it must be the front callipers sticking now, and I exercised the pistons, pushed them out and then forced 'em back in a couple of times and then eased up a bit. Now I can push the car w/o too much effort but I guess both need a rebuild.

Funny thing is though... after doing this the brake fluid level has gone down noticeably.

=S The floor is still squeaky clean and I can't find any spots on the hoses/pipes/callipers/ABS-unit where it could have leaked out...

I've bled the system properly but I must have gotten rid of air by exercising the pistons somehow. Beats me.

[cabriodster87]

Search "brake line problems/ diagnoses" soft lines can develop rust "check valves".

Booster pressure can pump fluid into calipers thru restricted lines and hold, hope this helps.

EDIT: check this similar problem...http://ecomodder.com/forum/showthrea...-me-21019.html

[Peace_Power]

Search "brake line problems/ diagnoses" soft lines can develop rust "check valves".

Booster pressure can pump fluid into calipers thru restricted lines and hold, hope this helps.

EDIT: check this similar problem...http://ecomodder.com/forum/showthrea...-me-21019.html

Thank you!

I'll make sure to get some new soft lines to! (=