Inconsistent Brakes

chrischris · Post by **chrischris** » Fri Feb 23, 2007 3:23 am

The other day I noticed that when I first apply pressure to my brake pedal everything is fine, however if I release it and apply pressure immediatly again the brakes don't work well. Under these circumstances they feel just like when my vacuum pump valves were in backwards and I had no power brakes. I checked under the hood and it looks like my vaccum pump is leaking oil, all over the transmission case.

Does this mean I need to rebuild the vaccump pump? Do I use a so called diaphram kit?

bscutt · Post by **bscutt** » Fri Feb 23, 2007 2:15 pm

Probably needs a rebuild. get the valve kit too. I've found that the valves will get loaded up with oil and even if you clean them, they may not hold up. Best to replace the diaphragm and the valves. Note - there is a procedure for mounting the diaphragm that is critical to having it last more than a few months. If you have a Bentley manual, find that section and follow it.

tylernt · Post by **tylernt** » Sat Feb 24, 2007 2:16 pm

What bscutt said. I went through this not too long ago and I needed the valves as well as the diaphragm. Actually, my valves may have been ok, but I think the gasket for the pump's valve cover was leaking air between chambers. The new valve kit comes with a new gasket so you're covered for either problem.

There is also an O-ring where the pump sits on the engine block. I got one for a few pennies at my FLAPS.

chrischris · Post by **chrischris** » Sat Feb 24, 2007 8:00 pm

What type of kit do I need to buy? My local napa had a valve rebuild kit that included the valves and small gasket. Do I also need the larger gasket as well?

tylernt · Post by **tylernt** » Sat Feb 24, 2007 9:10 pm

There are two separate kits. One has two valves (look like pants buttons) and a four-sided gasket. The other has a big (3" or so) round rubber thing (the diaphragm), a new 10mm locknut, and a five-sided gasket. Jack (owner of this website) sells the diaphragm kit, FYI.