s-10 dual diaphram booster fierostore big bore master fierostore big front brake upgrade reman stock rears new ebrake (all lines/springs) new lines and hoses This is "Formula'"s car.
I was on the expressway for about 3 miles then all of a sudden the brakes started to engage. I had this happen while DH and I were tuning the car also but I thought they just stuck from sitting or something. This time the engaged all on their own. I tapped the brakes a few times and it didn't release. I would say it was giving about 30% pressure. After about a half mile I pulled off to the side. I left it running. I had a infared thermometer and the front brakes were both 600*, the rear 200*. I let it cool for 15 minutes and it was still dragging. I remembered when it happened before we pulled it into a gas station and shut it off while I looked for anything kinked lines etc. So while on the side of the road I shut it off for a minute and then restarted it. The brakes released and it was fine for the rest of the trip.
Any Ideas? Only thing I can think of is the booster related.
I've driven it over 100 miles and it's only happened twice.
Change your flex hoses. They rot from the inside. you can get a nice braided set from ebay, all four corners for under $50!
What I think is happening is the flex lines are rotting inside causing resistance. This is in turn not letting the caliper retract fully. My guess would be 5% braking pressure. This causes heat and the rotor will expand and increase the clamping pressure caused by the caliper. Hotter in gets, the more it expands and jams.
It`s the first quick fix I would be doing. And at the same time it would change the brake fluid.
Check the brake fluid in the master for an overfilled condition. Once I changed out the pads and didn't notice the master had become overfilled, took it for a drive and once the fluid started to heat up and expand, it started to apply the brakes (no where for excess pressure to expand to). Removed some fluid and all was good again.
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01:19 PM
gen2muchwork Member
Posts: 861 From: dearborn, MI Registered: Feb 2012
There could be a lot of things, but if you think the hoses and calipers are all good and the ebrake functions correctly and the sliders are all free and there is no air in the system, I might guess the pushrod is mis adjusted not allowing the master to return completely.
Ok, I have more information. I'm out driving it and could feel it start to drag. I pulled into a parking lot. It won't move at idle in park or reverse. I popped off the master Cylinder lid and there was no change. I pulled the vacuum line off the booster and it freed right up and will now easily roll back and forth. I hooked the vacuum Line back up it would still roll easily.
I took it for another spin a few hours later. Brakes started to drag again so I pulled the vacuum line and reconnected it. After a few hundred feet they would start to drag again. I had to leave the vacuum line off and have manual brakes the rest of the way home. It glided so nice! ---------------- Turbo3800E85F23 5spd spec5 11.17@132.6
[This message has been edited by Justinbart (edited 01-30-2013).]
When I installed the S-10 booster into my Friend's 86 GT, I had the same issue. It started to drag, and it actually got pretty bad. So we pulled over, wondering what it was, having the living Sh*t scared out of us because his dad left a coat-hanger in the rad fan area and the fan turned on...anyway, what I did was, I grabbed the brake pedal and yanked backwords, and it actually moved back. He had the brake switch and the threaded coupling too far forward, thus causing the brakes to start dragging, heat up, and get much worse.
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01:45 AM
Fierobsessed Member
Posts: 4782 From: Las Vegas, NV Registered: Dec 2001
Mine S10 booster actually has a hard time disengaging for an instant while letting off the pedal. Like if Im braking at threshold, and achieve a little lockup, releasing the brake does not necessarily unlock my wheels instantly like it should. Modulation is very difficult to maintain. I know its the booster, it was the only change at the time this issue popped up.
