The Stovebolt Site Forums The Parking Lot Big Bolts 57 6500 brakes

Hello all I got my kingpins and bushings done adjusted the sector drives like new now on to the brakes I planning on rebuilding the hydravac reman in Atlanta has the parts and having them reline the park brake shoes. As it is right now u have pump the brakes a few times to stop It's losing fluid through the booster I hope the rebuild will fix that no wheel cylinder leaks and the shoes look good I guess my ? Is what size bore should my master cylinder have the guys I bought the truck from had put a new one on I wonder if they put the right one on I'm also planning on replacing lines and hoses all you guys that order from rock auto how are y'all looking up big bolt parts if I do a parts search for a 6500 all I can find are parts for a one ton down Thanks in advance Kip

Hy Kipparham, go on google and type in Raybestos brakes, when it opens up click on the heading that says catalog [not home], now you select medium duty truck, then year, then make, then series. Then you can either select the specific parts you're looking for, or select all and scroll through. Write down all the part numbers you are interested in. Now go over to the Rock Auto site, and do a part number search, enter the part number, then select Raybestos from the drop down manufacturers list and press search. That will tell you if they stock the part and how much it is, hope that helps.

Are you losing fluid or just having to pump the brake to get pedal, and once you get pedal and hold pressure does the pedal slowly continue to move towards the floor.

ABento it losing it through the booster it takes a while to lose a master cylinder full but it's going to the engine through the vacuum line after you pump them a few times it has and mantains a good pedal till it's time to stop again

Kipparham,

Putting the leak aside, the problem you discribe with the pedal could be due to the brake shoes needing adjustment. If the shoes are to far away from the drum it takes more fluid to get them to make contact than you get with one pump. Along those same lines of thinking, if the Master Cylindar bore is to small you can't push enough fluid in one pump either.

If I remember correctly the 1-1/2 & 2 ton Chevy trucks use a MC with a 1-1/4" bore.

Hope this helps,

Mike B

Y'all bring up alot of possibilities I think I will go ahead with the hydravac rebuild first. Then maybe check the mc is there anyway to check the bore size without taking it off and tearing it down I checked the adjustment believe it or not all the adjustment wheels were free I tightened till I got a little drag then backed them just enough for them not to drag.

Bore dia. is pressed into the side of the MC when it's cast. With a wire brush and a flashlight it should be easy to see.

Mike B