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Old 03-14-2014, 08:31 PM   #15
motornut
78K & 79C Jimmys
 
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Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
Re: Too much travel before brake booster kicks in?

Quote:
Originally Posted by JLeather View Post
Yep, bone stock brakes. 13" drums in the rear and whatever the HD discs are up front.

Got the new m/c in and the results are mixed and somewhat disappointing. As soon as I put it in I got fluid to the back brakes, so that does indicate that my old m/c wasn't generating any pressure to the rears. The rears bled nicely, starting at RR and then LR. At that point the pedal was pretty firm at about 2" of travel. Big improvement. Went up to the fronts and bled out a lot of air, not surprising since before the m/c acted like it was pumping air in with every stroke. The pedal felt nice and firm, no more air was coming out of the brakes, etc.

Here's where it gets disappointing. As soon as I started the truck the pedal went back to being extremely squishy, travelling almost to the floor. The truck stops again at least, but it takes a solid 5"+ of pedal travel before the brakes even start to drag, and it's almost on the floor when the truck stops. I'm going to let it settle and try bleeding the brakes again tomorrow. I can move the truck around, but not comfortable enough to try driving it.
Your brakes may need to seat
Or the rears need adjustment
try the e brake ,they are different systems, but if that doesn't work , it still needs adjustment
If the adjusters etc are working, backing up and hard stops can adjust it.
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John
1978 GMCJimmy4X4-350/203
1979 GMCJimmy4X2-305/350
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