Former VWDieselParts.com Forum

I've got two 81 rabbit diesels and niether one has decent brakes. I replaced the brake booster and master cylinder on one to see if it helps and no difference. All other brake parts on that car are new. The only thing I can think of now is the vacuum pump. How much pressure should there be or can anyone suggest something else?

Checking the vacuum pump is easy with a cheap vacuum gauge. If it's bad, you can get a rebuild kit pretty inexpensively from this site's sponsor, Jack. It's pretty easy to install: just make sure that you get the notch in the end of the shaft indexed into the oil pump or you'll have no oil pressure. It won't hurt to check the vac hose while you're at it.

Make sure you have no vacuum leaks anywhere---at an idle it is easy to loose the boost

You might try upgrading to the later vacuum pump off of an A-2 model

I see around 25" Hg on my vacuum pump when running, a little lower at idle.
Vacuum pump would be the first thing to check with hard to push brakes.

joenbarb wrote:I've got two 81 rabbit diesels and niether one has decent brakes.

Define Non "decent brakes". What exactly is the issue? Is the brake pedal too high and hard? Too Soft and low to the floor? Do you have an external leak anywhere? What % of brake pad material is remaining front and rear? When did this issue start?

bottleworks wrote:Define Non "decent brakes". What exactly is the issue? Is the brake pedal too high and hard? Too Soft and low to the floor? Do you have an external leak anywhere? What % of brake pad material is remaining front and rear? When did this issue start?

You seem like a logical thinker! I like that!

What I mean by non decent brakes is that all of the brake parts are relatively new and you couldn't lock the brakes if your life depended on it.
If you are going 40mph you need to leave several car lengths in case something happens.

Joenbarb, I was wondering if your idea of poor brakes is that the brakes won't lock up. My 82 Rabbit has been in my family since new. Dad owned it before I did. I have never ever been able to lock the brakes, even in a panic situation. However, as long as your brakes are working effectively and not taking way too long to stop the car, you don't need or want the brakes to lock up. You get maximum braking at the point just before brakes lock up - hence anti lock brakes on new cars. Is the stopping distance poor?

my golf is the same way, rock hard pedal and all brake parts are like new- its the vacuume pump... Just today I had to go off the road because somone saw an old car and figured it was going slow and pulled out... I was at 73mph when they pulled out. Lucky for me the sholder was large and the left 2 tires stayed on the pavement as i blew past the dude on the bike lane. I use the hand brake daily in pannic stops