Just how bad is it to have to change this bugger on my '87 convertible? :eek: Are under dash contortions required like on the C3s? Also, how do I tell if the PB Booster is bad / going bad? Do they totally fail or are they intermittent? My pedal occasionally gets a bit soft. The pedal looses some pressure and goes down a big lower before you get the braking power, and it takes more leg power. I know the MC is leaking a big. Could this be the booster going too or is it likely just the MC? I've got a new GM MC on order, I'm wondering if I should swap it, bleed the system etc and then see what happens, or is there a way to tell if the booster is bad before I dig into the system? Thanks, ~Juliet

 

I would just change the MC and bleed the system. The symptoms that you are giving are not indicative of a bad booster. You can check the booster with a vac pump/gauge setup.

As for how hard to change it, it's not bad at all. The under dash stuff can be done while sitting on the floor outside the door of the car. I used a long extension and a universal with a socket and got all 4 bolts out no problem. Then you just reach up there and remove the little clip that hold the rod onto the pedal. Not a bad job.

 

Agree, it sounds more like you have a bad master.

I just replaced the booster in my 89, sure it's the same.

Only hard part was getting the nuts back on. My hands won't reach up there. Rest of the job was probably an hour.

Finally my buddy came over with a flex (spring type) extension from snap-on. He used masking tape on the inside of the socket and forced the nut into the socket for a pressure fit. Then used that extension/socket/tape to start the nuts. Once started I just drove them home. My bud took about 5 minutes, and I another 5 to get it torqued properly.

NOTE: when I tried to start the nuts w/o the above method, I generally droped them. 90% of the time when dropped, they dissapear behind the firewall insulation. If you remove the booster - with a little luck you can then retrieve the nut(s). If the nut(s) drop too low in the insulation, good luck. BTW, the nuts are a flair end crimped locking type I could not find in a parts store.

One more booster item. There is an adjustment between the booster and the MC. The adjustment is on the booster. I used a steel rule as a flat edge and measured the gap with a feeler guage. Matched this gap on the new booster. Was way too tight after about 150 miles, don't know why. Haven't been home enought to fix this yet. Suggestion: If you buy a GM new booster, leave the adjustment as it comes. If the pedal is too low, it takes about 5 minutes to seperate the MC from the booster and adjust the booster. This is what I would do in retrospect.

Good luck.

Pete

 

Thanks for the great inputs & tips guys. :) The new MC should arrive next week. I hope to get to it over the holidays. ~Juliet