Soft brakes - check your booster adjustment

[nrubenstein]

I feel pretty stupid right now, but at least I've fixed my soft brakes.

Not much else to say, really. If you have perfectly functional brakes, but a significant amount of travel before they do anything, check this. It could easily mean that your booster clevis is too short.

[jrdeamicis]

Only if more people would be willing to admit their mistakes so we could have a comprehensive collection of mistakes and solutions..

Thank you!

[mr.vang]

how do you adjust it?

[MaxBell]

OMG, I just posted asking about this problem!! What do I do??

[static]

got this problem, how do i troubleshoot?

[nrubenstein]

For starters, the feeling is almost exactly like air in the system that just won't bleed out. Which is annoying because it makes it rather hard to identify. This makes it unlikely to be the cause of soft pedal issues in a normal E30, but pretty likely in a swapped car.

The way that you adjust this is by disconnecting the booster clevis from the brake pedal and then extending it out. My method was to adjust it out until I just barely had to tug on the brake pedal to slide the pin in. Half a turn in from there would probably have been just fine, and half a turn out would lock the brakes. (My test was whether or not I could easily push the car.)

Note: Access with the booster in the car is poor. If you can't easily get the booster clevis loose, remove the pedals. It's VERY easy to undo the big bolt that holds the pedals on to the pedal box and get both of them out of the way. I do not believe that I could have applied the necessary torque to the lock nut without doing that.

Also, the booster rod can spin in the booster. When you are done testing, put the lock nut back on. I don't know how likely it is that it'll spin under use, but it is possible.

[static]

Hey thanks, i also get that swooshing noise when i press the pedal while it's traveling the distance until it hardens. Is that one of the symptoms too or something else?
I was blaming the air trapped in the ABS pump for the soft pedal, but i'll try this

[nrubenstein]

Hey thanks, i also get that swooshing noise when i press the pedal while it's traveling the distance until it hardens. Is that one of the symptoms too or something else?
I was blaming the air trapped in the ABS pump for the soft pedal, but i'll try this

The swooshing noise is generally just the sound that the booster makes. When the brakes are working correctly, you won't hear it in normal use, but it's there whenever you are using a lot of travel.

If you're confident in your brake bleeding, or even if not, this is easy to check and free to fix. That makes it fairly high up the list of things to do when troubleshooting a car that has had the booster altered.

[e30rapidic]

kudos for admitting/posting this. No worries I did the same thing in my racecar....

[MaxBell]

Interesting. When you say "disconnect the clevis and extend it out" you're refering to this?



And I want to move it back on the threaded rod, away from the booster?

[nrubenstein]

Yes. Lengthen the rod if it is a little short when you disconnect the clevis from the pedal pivot.

[Wh33lhop]

Fuck me sideways. I've had soft brakes for a long time after repeated bleedings (sinks an inch or two and then firms up). I'm gonna check this and report back.

Edit: damn. Wasn't the problem, although I was only able to get the clevis to align with the pedal all the way out. Couldn't go any further.

[lolcantturn]

Won't this get the pedal closer to the floor? Essentially you're removing the "dead soft spot" and getting the pedal closer to the floor right?

[Wh33lhop]

No. This would do the opposite.

[Blaine0002]

Fuck me sideways. I've had soft brakes for a long time after repeated bleedings (sinks an inch or two and then firms up). I'm gonna check this and report back.

Edit: damn. Wasn't the problem, although I was only able to get the clevis to align with the pedal all the way out. Couldn't go any further.

are you running a spacer in your setup? if you are, set the clevis further in and just remove the spacer and adjust from there.