Asha'man

iTrader: (1)

I've alluded to this issue in some other threads, but here's the problem. When I'm driving around sometimes, the car will suddenly and randomly bog down. I can let off the gas and it will cruise quickly to a stop and stay stopped, even in D and my foot off the brake. Usually if I tap the brake pedal a few times it disappears, but it happens frequently enough and sometimes severely enough that I'm not comfortable leaving it. The first time it happened I pulled out the ABS and TRAC fuses, thinking it could be either of those systems acting up. That time, my front wheels were too hot to touch and my brakes smelled like they were burning up, so there was definitely some locking of some kind going on in the front.

What might cause this? Obviously sticking calipers could do it, but it seems unlikely that both sides would go out at the exact same time, and do it repeatedly. Is there a chance that the ABS or TRAC ECU's could be firing and setting the brakes without a reason? Or would those even work with no fuses? Any input would be awesome.

StiCk3

iTrader: (5)

check the fluid and see if it is dark in color. Leaking calipers can get on the pads and make them feel "sticky." I wouldn't rule out sticking calipers on both sides just yet.

PERRYinLA

I had this problem on my '72 BMW 3.0cs, and I narrowed it down to the vacuum booster somehow applying slight, constant pressure to the brake master cylinder even with my foot off the brake.

I never could find out how to fix the vacuum booster and didn't want to replace it but my workaround was to remove the brake master cylinder and reinstall it with a 1/8" - 1/4" gasket, which moved it forward just enough so that the vacuum booster no longer applied pressure unless I hit the brakes.

Brake systems have come a long way since then so you probably don't want to try my workaround but it's still possible your problem is also coming from the vacuum booster.

Amini9

WTF. same thing happened to me today!

I'm driving on a flat road that i usually stroll through without the gas and it stops in the middle of the road slowly. Then it sat back (as if you applied the brakes lightly to a stop)

I'm 16, have no experience... what is the easiest thing to check out myself?

scENFORCER

Master Cylinder. You can release the pressure by slowly unscrewing a nut thus releasing the pressure/breaks (but dont totally unscrew it). I had the exact same problem as you, I got a new Master Cylinder and the car was fine after that.

Asha'man

iTrader: (1)

Interesting. In what situation would one release the pressure using that nut?

scENFORCER

..when the breaks come on. You cant really drive like that, so pull over and release the pressure which releases the breaks. Some break fluid will leak, so make sure its only 1-2 drops by only loosening the nut a TINY bit at a time, until you feel the breaks release. You'll have to make sure ur break fluid levels are ok though, until you get a new master cylinder.
I posted the same issue, ill try to find my old post for you..

scENFORCER

Here you go..
https://www.clublexus.com/forums/sus...em-breaks.html
https://www.clublexus.com/forums/sus...-cylinder.html

Asha'man

iTrader: (1)

Your old thread on the master cylinder labor just came BTT today, so I read through it. Did that end up solving the problem?

scENFORCER

Yes it did..