Power Disc Sawp Braking Problems
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Senior User
Joined: Sep 2002
Posts: 306
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From: United States
Power Disc Sawp Braking Problems
Hi!
I'm having some problems with braking that don't make alot of sense. The truck has the disc brake swap from a 75 model and a MP brakes booster. Most of the time the truck stops just fine with a good pedal. But every once in a while I'll have practically no brakes. This usually occurs at low speed and pumping doesn't make much difference. I've bled the brakes more times than I can count and really doubt there is any air still in there.
Any ideas?
Thanks!
Larry
I'm having some problems with braking that don't make alot of sense. The truck has the disc brake swap from a 75 model and a MP brakes booster. Most of the time the truck stops just fine with a good pedal. But every once in a while I'll have practically no brakes. This usually occurs at low speed and pumping doesn't make much difference. I've bled the brakes more times than I can count and really doubt there is any air still in there.
Any ideas?
Thanks!
Larry
Postmaster
Joined: Apr 2002
Posts: 3,613
Likes: 6
From: Coal country
Power Disc Sawp Braking Problems
I assume you still have power assist when this occurs. That is, the brakes are soft, you feel like you're stepping on a plum (where did that come from?! Anyone??)
This is a classic symptom of a failing master cylinder.
Get it changed soonest, before it fails completely.
Now if I am assuming incorrectly, that you instead have a hard pedal instead of a soft pedal when this happens, then you have a failing booster, a plugged vacuum line filter or valve (if so equipped), or vacuum leak. If it is a leak, you will hear the engine speed change, though, either up or down, due to the leaner mixture.
This is a classic symptom of a failing master cylinder.
Get it changed soonest, before it fails completely.
Now if I am assuming incorrectly, that you instead have a hard pedal instead of a soft pedal when this happens, then you have a failing booster, a plugged vacuum line filter or valve (if so equipped), or vacuum leak. If it is a leak, you will hear the engine speed change, though, either up or down, due to the leaner mixture.
Thread Starter
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Senior User
Joined: Sep 2002
Posts: 306
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From: United States
Power Disc Sawp Braking Problems
Thanks Guys!
I replaced all the vacuum hoses and checked everything for leaks. It all looks good but same symptoms. The booster is definately working as the pedal is soft. I'll move on to replacing the brand new MC now.
Larry
I replaced all the vacuum hoses and checked everything for leaks. It all looks good but same symptoms. The booster is definately working as the pedal is soft. I'll move on to replacing the brand new MC now.
Larry
Thread Starter
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Senior User
Joined: Sep 2002
Posts: 306
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From: United States
Power Disc Sawp Braking Problems
Thanks for the help. I now have good brakes all the time. The problem was that the rear DS brake assembly came apart. I had a friend drive the truck while I walked along side and listened to the wheels. I could hear something dragging in that area. The adjuster, a spring, and that big flat bar came falling out when I removed the drum. I don't know why as they are all brand new but I must have done something wrong in there. All is good now!
Larry
Larry
