Author Topic: Uhh, help! Please! (Read 4538 times)

didgeridoodude · « **on:** December 20, 2011, 12:28:28 AM »

So as I was pulling into my driveway tonight, it felt a little tougher than usual and I was quite puzzled. I finished pulling in, turned the car off and back on. Rolled over and then went off out of nowhere. Tried again, rolled over and was fine, revved the engine, everything was dandy. Did it again, same result, just great. But I decided to try to see if it could roll, so I put it in gear (tried both first and reverse) and it felt like the car had the E-brake stuck on (it wasn't, I made sure) and thus it would not roll anywhere. The rear brakes smelled and were blazing hot while the front brakes didn't share the problem.. Quite puzzled.. Any thoughts would be awesome.

Currently just letting her sit in the driveway and cool off.

bmwman91 · « **Reply #1 on:** December 20, 2011, 02:03:42 AM »

I would jack the rear wheels up and try to spin them by hand with the transmission in neutral. If you have a limited slip diff, you need to jack both up at the same time. From there, I would try to determine if the issue us brake-related, or driveline-related. Were both rear wheels/brakes extra hot, or just one side?

didgeridoodude · « **Reply #2 on:** December 20, 2011, 02:29:38 AM »

both were, although I have no jacks laying around to use.. and the one in the trunk is shit

DesktopDave · « **Reply #3 on:** December 20, 2011, 07:12:22 AM »

I'd suspect the parking brake. Check your brake fluid level...if that's OK I'd strongly suspect the cables are caught up in the cabin or rusted solid in their channels.

Could also be corroded rear rotors. Also, if the brake fluid level is low check the rear lines & hard lines for leaks.

d.hitchcock · « **Reply #4 on:** December 20, 2011, 08:11:07 AM »

+1

Sounds like seized parking brakes.

dh

didgeridoodude · « **Reply #5 on:** December 20, 2011, 10:28:39 AM »

Well, I got in the morning and tried to roll it, everything was fine, rolled in first and reverse. I'm almost positive it wasn't anything like cables or fluid because my mechanic just recently did a thorough bumper to bumper check and saw nothing wrong and neither did I.

Geoff · « **Reply #6 on:** December 20, 2011, 10:46:36 AM »

if you are sure its not the parking brake, then maybe the flex lines in the back are bad. sometimes, they will swell internally, letting fluid go thru under pressure from the master, but it cant come back out so the brakes stick on and get hot. hours later when everything cools down, the brakes release.
one possible scenario, you may have some other malady..
Geoff

bmwman91 · « **Reply #7 on:** December 20, 2011, 11:50:47 AM »

Yikes, never heard of the brake lines swelling before!

Aren't the parking brakes separate? Each as its own cable & stuff...it seems unlikely that BOTH would go at the same time. Or, am I missing something?

Geoff · « **Reply #8 on:** December 20, 2011, 12:28:23 PM »

the flex lines swell up inside, not allowing the fluid to escape. this is on your regular rear brakes, tho, not the emergency brakes, which are cable operated and you feel that they are ok. so, maybe that is what it is. many folks do not replace those flex lines and after many years, they can indeed swell up inside and close off..I have actually seen it, on my e-21 tho, not my e-30.
Geoff

bmwman91 · « **Reply #9 on:** December 20, 2011, 01:56:03 PM »

Aaah, yeah I was asking about the e-brake cables. It seems unlikely that both would fail at the same time.

The flex hose thing make sense. Both have had the same fluid in them for the same amount of time.

didgeridoodude · « **Reply #10 on:** December 20, 2011, 04:12:52 PM »

Dramatic update. On the freeway this morning it began to be very hard to accelerate and I decided I needed to get to school and finish my finals, so I ignored it. As soon as I got to the off ramp, my rear brakes started smoking and everything was just horrendous. Currently is in my shop getting looked at..

DesktopDave · « **Reply #11 on:** December 20, 2011, 06:20:22 PM »

Sorry to hear that.

Isn't there a rear proportioning valve on our cars? Lemme check.

When's the last time you bled the rear calipers?

If you have too much air in there, they won't retract.
If you have too much water in there, it'll boil to steam when they heat up & they'll lock up.
If you didn't clean the caliper pistons really well, the pistons will force that crud back into the seals and wedge the pistons. They'll extend easily but not retract.

An e30 seal kit is cheap, like $10/side. It's only two o-rings. If you're confident enough to attempt it, let us know. If not, have your mechanic swap them out. It'll only be like $200 or so. Better safe than stranded and sorry.

didgeridoodude · « **Reply #12 on:** December 20, 2011, 07:21:36 PM »

Well I just got the diagnosis, it was the master cylinder! So I need to replace that, the rotors, the pads and the calipers now anyway. I might be doing to the labor myself and with a buddy because they're asking shit tons of money.

DesktopDave · « **Reply #13 on:** December 20, 2011, 09:05:47 PM »

Are they sure? If it was locking up both the fronts and the rear I'd suspect the master cylinder.

Have you run some new brake fluid through the system? It's not hard to do, should only cost you about $10 for a quart of fluid.

IIRC the car has a rear brake splitter on the firewall below the brake booster. That sets the amount of fluid that heads to the rear brakes. Maybe it's clogged?

bmwman91 · « **Reply #14 on:** December 20, 2011, 11:48:14 PM »

Since the BMC has 2 pistons (one for front, one smaller one for rear), it is feasible that the one for the rear somehow seized. Keep us updated!