300 tdi vacuum pump

[jx2mad]

I realise that there a lot of threads on this component and I do not wish to dig these up again. However, I am about to repair my leaking pump and my mate (mechanic who owns 2 disco's) questioned the possibility of replacing the diaphragm whilst apart. He considers that after 10 years of use it may be starting to become brittle. Any thoughts on changing diaphragm at same time? Jim

[abaddonxi]

Just in case.:angel:

http://www.aulro.com/afvb/good-oil/42516-brake-vacuum-pump-300tdi-rebuild-instead-replace.html?highlight=vacuum

[isuzu110]

I've just completed a 7000k trip (Brisbane-Ayers Rock- Brisbane) where my vacuum pump died on my 300TDi defender. It was less than 12 months old and was a WABCO one. The booster is the same age.

It failed at Glen Helen on a Saturday morning and I there was no answer from Sutton Motors. They obviously don't work Saturday mornings (is there a dealer anywhere who does these days ?) so had to wait till Monday to order one direct from Brisbane. Had a new Wabco one flown into Yulara and had to drive for several days (~1000Km) without a working pump.

I jury rigged the input from my onboard air compressor to suck from the master cylinder in the meantime. It took about 2 seconds for the booster to get enough vacuum to kick in and I had to periodically run the compressor and anticipate most braking actions (towing a camper trailer). I didn't want to run the compressor continuously for fear of overloading the compressor or the booster.

The spring on the old pump seems to have failed. Just under 12 months old....

They don't seem to last. An expensive spare to carry for my next big trip <sigh>

[PAT303]

My original lasted for 10 years,the replacement 12 months.Mine just leaked as there was no loctite on the screws.I can't believe the pumps are made without any locking compound on them. Pat

[dham]

I have also just had a WABCO fail after less than 40,000 kms - original did more than 200,000 km! Only replacement that I could get is another WABCO which does not bode good. The Rovacraft parts man said that none of the pumps they have stocked have been much good - intrinsically a poor design?

[isuzu110]

Someone suggested that a fault in the booster may lead to a premature failure in the pump. I'm not sure how this could be given the pump runs continuously off the side of the block.

Can anyone think of how an issue in the booster could cause a premature pump failure and how you would test the booster ?

[steveG]

Only thing I can think of is that if you have a leaking diaphragm in the booster you might suck in dust etc.

There are instructions posted somewhere for how to test the booster, but basically its along the lines of:
- turn off the engine
- wait about 10 seconds
- apply and release brakes
You should get at least a couple of applications of the brake before it goes "hard" due to lack of vaccuum.

Steve

[BigJon]

I

It failed at Glen Helen on a Saturday morning and I there was no answer from Sutton Motors. They obviously don't work Saturday mornings (is there a dealer anywhere who does these days ?)

As far as I am aware they still open on Saturday mornings, unless it is a long weekend.