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#1 |
Registered User
Join Date: Jul 2013
Location: Livermore, CO
Posts: 136
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C30 - grabby power brakes
I have a '65 C30 283 4-speed that has a strange behavior. The factory power drum brakes seem to work okay but come on all at once after a long push on the brake pedal. The brakes take almost no effort to lock up. The truck has what looks like the original master and booster.
At some point I will switch to a dual circuit drum system so if the issue with the grabby brakes I have now is the old booster, well now is the time to make that swap. Any tips on that swap would be appreciated also. Thanks...ned.
__________________
'63 C10 long wide; '61 Corvair Lakewood; '74 BMW 2002tii; '89 BMW 325i, '49 Ford 8N |
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#2 |
Registered User
Join Date: Feb 2013
Location: central California
Posts: 2,735
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Re: C30 - grabby power brakes
When my stock set up did that, I yanked the booster converting to manual and it fixed the problem. Not knowing why it grabbed, I put the booster on the shelf hoping to figure it out later as it looked fairly fresh. After a while, a buddy tried it on his truck and it still grabbed so it went in the trash. Wish I was more help but thought I'd at least relate my experience.
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#3 |
Senior Member
![]() Join Date: Nov 2010
Location: Hays, KS
Posts: 2,490
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Re: C30 - grabby power brakes
I know the master cylinder is less than a year old, but also wasn't driven daily. But sounds like a vacuum booster to me especially being the original one
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#4 |
Registered User
Join Date: Jul 2013
Location: Livermore, CO
Posts: 136
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Re: C30 - grabby power brakes
Thanks Dylan and Dave. A faulty booster was my guess but I have not seen this mode of failure before. It's good to know the master is pretty fresh.
...ned.
__________________
'63 C10 long wide; '61 Corvair Lakewood; '74 BMW 2002tii; '89 BMW 325i, '49 Ford 8N |
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#5 |
Registered User
Join Date: Jul 2013
Location: Livermore, CO
Posts: 136
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Re: C30 - grabby power brakes
Followup for future thread searchers: a Cardone reman booster #54-73535 solved the problem. Brakes might need some adjustment but the pedal feels pretty good now and you can modulate the brakes to smooth stop. Been a while since I have driven power drum brakes. They have a different feel than modern brakes and I think a majority of the remaining pedal effort would go away if I cleaned and lubed all the linkage bushings! A light touch is all you need.
Thanks oldtruckguys...ned.
__________________
'63 C10 long wide; '61 Corvair Lakewood; '74 BMW 2002tii; '89 BMW 325i, '49 Ford 8N |
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#6 |
Registered User
![]() Join Date: Jan 2002
Location: norwalk,iowa,usa
Posts: 921
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Re: C30 - grabby power brakes
these old 64-66 power boosters are easy to rebuild ! the tricky part is disengaging the two halves /ive done mine in a press .Twist the two halves in opposite directions then clean & check the insides and rubber diaphram -90 per cent of the time the diaphram is OK.THEN BLAST OR CLEAN UP THE HALVES OR CAD PLATE or powdwer coat them and reinstall with a new boot -which can be bought off e-bay or cheaper at the chevy dealer {using a newer part #} also cleaning up all mounts and the aluminum wedge and lubing all pivoy points /should work as good as new /if cleaned it looks better thaN that off/shore booster kits on evil bay- GOOD LUCK MIKE
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#7 |
Registered User
Join Date: Apr 2014
Location: Rochester, MI
Posts: 206
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Re: C30 - grabby power brakes
Dear ncoonen, I'd like to hop on your post. I have a half ton with a power booster and dual circuit upgrade. It's prob been on there for 5-6 years. The booster appears to be a Cardone. The brakes have a light touch but I got used to it.
A few points for your consideration or input. 1. Did you have to adjust your push rod or did you keep the longer pedal? 2. My brakes are grabby if I need to make an abrupt stop. Otherwise they are ok. Have you made any sudden stops yet? 3. My master cylinder looks contaminated so I plan to change. (awaiting a suggestion as to type of unit to buy- posted a thread yesterday) 4. I learned on this site, and also research, you don't need a proportioning valve with drum-drum brakes. I initially thought that's why they were grabby but apparently not. 5 Lastly, I put a hose up to back of power booster from inside the truck (where push rod enters) and here a faint, continuous hiss. Same air sound whether brake is depressed or left out. Pedal is not hard to push so I'm thinking a little air sound is acceptable. Can you hear a slight air sound from back of booster inside truck? Since we both have Cardones, I would greatly appreciate some feedback on #1 and #5. Thanks |
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