Booster pump
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Booster pump
I have posted several times about my brakes and after some reading and plain curiosity I've narrowed it down to my booster pump applying pressure to the brakes on its on. The faster the motor turns, the harder it pushes.
Orylies has a new one for $120. Is that my only option or can I repair the old one?
Orylies has a new one for $120. Is that my only option or can I repair the old one?
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
Do you have a hydroboost, or vacuum pump? A vacuum pump only supplies vacuum, if the brakes are applying on their own, the brake booster on the firewall is to blame. If you have hydroboost, and the brakes are applying on their own, there is something wrong in the valving.
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Well maybe not litterally but it's not bad when you first start but after you get on down the road they really set in. We removed the vacuum hose from the booster and the pressure was gone immediately.
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From: Peterborough, Ontario
The brake booster isn't 'serviceable', if it's pooched, replace it.
I've said it before, I'll say it again, IMO, it's best to replace the booster and the master cylinder as a unit though.
I've said it before, I'll say it again, IMO, it's best to replace the booster and the master cylinder as a unit though.
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Yeah I really didn't think thee was anything you could do for it... But asking never hurts. I most likely will replace both together. Thank you
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Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
The vac pump only supplies vacuum, it does nothing more. If the brakes apply, it is due to the booster, not the pump. It replaces the engine vacuum since the diesel motors do not produce vacuum when operating properly. Of course when you remove the hose, you have no vacuum, you also have no brake assist, that is all done by the booster, the vacuum is the energy used to make the booster help apply the brakes. It is down to either the booster valving is bad, or the brake pushrod is actually offset from its neutral position, and causing the booster to act like you are pushing on the pedal. Replacing the vacuum pump may actually make this issue worse if the vacuum were to be lower than a new one. They are regulated to a certain vacuum pressure, but it gets lower with age.
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The power brake booster is what I'm referring to, not the actual vacuum pump.
The pushrod is a possibility but I've already adjust it to its correct specifications. This had zero affect on the issue, only the peddle position.
The pushrod is a possibility but I've already adjust it to its correct specifications. This had zero affect on the issue, only the peddle position.
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Yeah I replaced everything except the steel lines going to the rear brakes and the drums haha. Now... I could change it and it still do it but it really looks like that's the issue. Maybe it's a diaphragm inside not letting the vacuum bypass, I have no idea but w the hose off the booster I have full stoke of the peddle and the brakes are free.
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