# 81 rabbit pickup brake questions



## Mxrath98 (Aug 9, 2015)

Hey guys I'm in the process of mostly restoring an 81 caddy got the motor running solid and everything it's a 1.6na diesel. The brakes are giving me a run for my money though, literally and figuratively. Here's a list of what I have already replaced in the brake system alone: front calipers, pads, rotors, rear drums, shoes, drum cylinders, master cylinder, and vacuum pump diaphragm. Unfortunately I am having the same problem as before I replaced all of this although the diaphragm did definitely help the problem but only at certain times it seems. Best way to describe is I get no power assist while braking. The pedal is rock hard and the brakes will barely grab it seems. And there is no air in the lines I sucked through about 2 quarts of fluid so I am certain that is not it and I did bench bleed the master cylinder as well. Sometimes after I am cruising for a bit the system seems to build up some vacuum pressure and I get to a of assist for a second or too as it slowly fades then goes away to no assist. I believe it is the booster itself now at this point but before I go spending money for a new one, I would like some inputs as to what it could be. I was also thinking the vacuum line and valve running to the booster from the vacuum pump. And the pump definitely has pressure now that the diaphragm has been replaced. Any help is greatly appreciated. Thanks!


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## Obysk (Aug 26, 2015)

If you're confident that all of your previous work was done correctly and with quality parts, next step, check the brake booster. This problem sounds like a faulty brake booster.


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## Mxrath98 (Aug 9, 2015)

Cool thanks that sounds good I appreciate the opinion. After I get the rust repairs done I will mess with the brakes again and see what I find out.


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## Blue-Civic-Hybrid (Jan 19, 2015)

Sounds like the same problem I have with my 82 caddy. I really have to put some serious pressure down to get the brakes to work. PLease update when you get a chance and let us know if the brake booster fixed your problem and where you got your parts from...


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## mk2addict01 (Jun 15, 2015)

Ok guys, I had the same problem in my 1982 rabbit pick up 1.6 diesel, and came out to be the vacuum pump, now my question to you is?...did you replace the pump it self or did you get a rebuilt kit for it..... In my case I bought the rebuilt kit for the pump, installed it and worked great, and my problem was same as yours, hard rock brake pedal with very minimal response, after I fix that I installed a 5 speed tranny in it and change spindle to have 100 mm axels fit, and install cross-drilled rotors, and is awesome now....check booster and double check vacuum pump, and please keep us posted.


Sent from my iPhone using Tapatalk


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## mk2addict01 (Jun 15, 2015)

Sent from my iPhone using Tapatalk


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## Prairie (Aug 5, 2008)

Sounds to me like you did not orient the inlet and outlet valves correctly when reassembling the vacuum pump. 
Look in a manual and see diagrams of which way they orient. They are part of the repair kit.

The old diaphragm vacuum pumps are crap anyway. In the future, start looking for a later model vane pump which will slip right in to the older vehicles.


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