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brake trouble

2583 Views 17 Replies 6 Participants Last post by  tommyboy8072002
96 chevy tow c3500 tow truck
i put all new brakes, calipers, hoses pads,master cylinder and new brake lines i even by passed my abs unit and i am still having trouble with my front brakes locking up when i ran new line from the master to the rear and master to the front with a 3/16 line front and rear but i think my back should of been 1/4 inch line would this cause the front brakes to lock up my rears are working fine they don't lock up like the front but some how i am getting too much presser to the front brakes i have to let the truck sit till the brakes cool down then start driving again
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tommyboy8072002 said:
96 chevy tow c3500 tow truck
i put all new brakes, calipers, hoses pads,master cylinder and new brake lines i even by passed my abs unit and i am still having trouble with my front brakes locking up when i ran new line from the master to the rear and master to the front with a 3/16 line front and rear but i think my back should of been 1/4 inch line would this cause the front brakes to lock up my rears are working fine they don't lock up like the front but some how i am getting too much presser to the front brakes i have to let the truck sit till the brakes cool down then start driving again
Because you say you have to let the truck sit till the brakes cool down sounds more like they are not releasing, not locking up. There is a difference. If they are locking up, they will skid your wheels. Is the problem with both front brakes or just one side?
S10 Racer said:
Because you say you have to let the truck sit till the brakes cool down sounds more like they are not releasing, not locking up. There is a difference. If they are locking up, they will skid your wheels. Is the problem with both front brakes or just one side?

Notice the use of puctuation and capitols in the reply to the OP. Makes it easy to understand the problem and results in more helpful replies.. JMHO :welcome: .
brake problems

Sorry both front brakes. Not just one side.
What about if i buy a proportion valve? And hook it up to the master cylinder to the front brakes. And the only one i can get is for a Buick car through Napa.
Would that work? Just wondering Thanks
tommyboy8072002 said:
What about if i buy a proportion valve? And hook it up to the master cylinder to the front brakes. And the only one i can get is for a Buick car through Napa.
Would that work? Just wondering Thanks
Read this and see if it helps
http://auto.howstuffworks.com/auto-parts/brakes/brake-types/master-brake2.htm
Well i guess i don't need a proportion valve. sense i don't have that kind of trouble.
Question what about if i run a 1/4 inch line to the rear brakes . Would that release enough pressure on the front brakes?
does anyone know if a Hydro boost would cause calipers (both front) not release
Changing brake line size will change nothing. Pressure on a hydraulic system is the same throughout the system regardless of line size.

Next time the brakes lock, open a bleeder in front. If they release the problem is the fluid is being held in the front, rather than released back to the master cylinder. The cause can be a misadjusted brake pedal, misadjusted booster pushrod, wrong master cylinder, something in the line acting as a check valve, or defective brake hoses.
yup your right i opened the bleeder screw and it released

Thanks i will check the Hydro boost push rods and see what i can come up with i will also check the master cylinder to make sure that it was the right one for this truck

Thanks again
I have looked at the Hydro boost and i don't see any adjustments on the push rods does anyone know if i could put washers in between the master and the Hydro boost to make up the space so it wont keep doing this
Thanks
My bro had this problem on his rat rod. The problem was that the pushrod for the master was TOO LONG. He had put an S10 setup in his '36 Plymouth. Apparently, the firewall was thinner on the car. Did you change anything else in this area? Adding a washer would probably be making it worse, unless you added them between the master & firewall.
Just re-read your post. Sorry, you did say between master & booster.
Thanks 1pickup no i have not worked on anything else in this area. Thanks for the heads up i am going to see if i can find another booster in the mean time i am going to see if the parts store sell spacers. If you think of anything else let me know
Thanks Again
tommyboy8072002 said:
Thanks 1pickup no i have not worked on anything else in this area. Thanks for the heads up i am going to see if i can find another booster in the mean time i am going to see if the parts store sell spacers. If you think of anything else let me know
Thanks Again
Felpro makes a Chevrolet thermostat gasket out of plasic with an O ring seal. Ir's the same bolt pattern as the master cylinder, and about .100" thick. You can use one of them as a spacer.

http://pitstopusa.com/i-5061702-fel...asket-sb-chevy-1-8-plastic-molded-rubber.html

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Ok I was just watching this show called Chasing Classic Cars last night and the same thing happened to them. So the cause for them was that the Master was bad and the booster locked up, they bleed the front brakes ONLY and it was good to go (except the brakes were out in the front). Might try that :)
Ok Thanks. If it does it again i will give that a try. What i ended up doing was using two thermostat gaskets in between the master and the booster and it hasn't done it yet. (knock on wood). :)
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