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RaDi90Hybrid

Vacuum Pump Oil Leak

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After an extensive search to track down the source of the oil which was being dumped on the drive under my Disco 300TDi I traced it to a leaking vacuum pump. The oil was leaking between the casing and the cover, not an uncommon problem apparently, and not wanting to part with the best part of £100 I decided to try repairing it, I had nothing to lose. The leak appears to be caused by the rivets securing the cover to the body becoming lose so the idea was to replace the rivets with nuts and bolts. The brakes on the vehicle were fine so it was only a case of re-sealing the cover. First I removed the pump from the side of the block.

Clamped it in the vice (carefully as it is only cast ally) and drilled the rivets out with a 4.5mm drill bit.

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Once this was done I carefully removed the cover waiting to catch any bits which came flying out……… result! Nothing

All that is loose is the 'o' ring.

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It is worth noting the shape of the 'o' ring and hence it is not worth buying an 'o' ring kit to manufacture a new one (I now know!)

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Next I cleaned up the surfaces and the 'o' ring carefully, refitting the 'o' ring into the groove and replacing the cover.

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I used M5 X 20mm bolts, washers & nyloc nuts to retain the cover, but had to grind a flat edge on the washers which went against the casing.

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Once complete I refitted to the vehicle.

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Great documentention of the repair, did mine about a year ago and managed to get a new o ring from wabco, 3.50! :D

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Interesting, because I have been told a few times that it doesn't work. I DO know that trying to fix a non-working pump is a waste of time as it is full of interesting bits of plastic that are made of unobtainium and tend to be of the 'pingon' type ie. you hear 'ping' and its 'gone' :o

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Interesting, because I have been told a few times that it doesn't work. I DO know that trying to fix a non-working pump is a waste of time as it is full of interesting bits of plastic that are made of unobtainium and tend to be of the 'pingon' type ie. you hear 'ping' and its 'gone' ohmy.gif

Update

Ran it up last night and then test-drove it and the pump is shows no signs of oil leakage. I did not try to 'repair' the internals of the thing, only trying to stop the leak from the end casing and it seems to have done the trick.

Andy

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Oil seems to be collecting in the circular recess of my vacuum pump hence I'm not entirely sure whether it's a leak from the casing ? could anyone shed some light on this for me.

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yesterday while off roading i finally managed to identify the source of my oil leak, and it's this pump

while the disco is leaning to the drivers side it dumps quite a lot of oil from the housing. now, my question is how do i know if the pump is leaking or knackered?

to me the brakes don't feel very good - never have in the 4 months i've owned it - but then again the brakes on my car are fantastic - so i can't really compare the 2...?

any help appreciated :)

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yesterday while off roading i finally managed to identify the source of my oil leak, and it's this pump

while the disco is leaning to the drivers side it dumps quite a lot of oil from the housing. now, my question is how do i know if the pump is leaking or knackered?

to me the brakes don't feel very good - never have in the 4 months I've owned it - but then again the brakes on my car are fantastic - so i can't really compare the 2...?

any help appreciated :)

Clean the oil from the back cover on the vacuum pump with a rag with some thinners, so its dry, you will probably then be able to see that the screws or rivets holding the back cover on are loose ;) , start up and you will see oil dripping or dribbling from the rear of the pump.

Follow the thread for repair as above, and happy days :D

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i can see the oil dripping without needing to clean it... :unsure:

so my question was whether the pump leaking causes the brakes to be a bit shady? so will fixing the leak cure the problem or do i need a new pump?

cheers

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I've a Disco 300Tdi in my 90. It's mounted in the same position as the original 200Tdi engine which means that it's closer to the bulkhead than if it was a 'proper' 300Tdi 90. The end result is about an inch of clearance to get the vacuum pump out. My question is: once the vacuum pump is unbolted how far does it need to be moved from the block before it's free?

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I've a Disco 300Tdi in my 90. It's mounted in the same position as the original 200Tdi engine which means that it's closer to the bulkhead than if it was a 'proper' 300Tdi 90. The end result is about an inch of clearance to get the vacuum pump out. My question is: once the vacuum pump is unbolted how far does it need to be moved from the block before it's free?

The plunger that runs on the camshaft is about 2 inches proud of the flange :( So with only 1 inch clearance its going to be a tight squeeze but doable I'm sure :P

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Just done this repair on a customers vehicle and it worked a treat, so thanks for that Andy :)

Les.

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Anyone know where I can get a blanking pkate for the vac pump? our TDi has ABS and no EGR so it's redundant and could go in the bin.

not really a good idea as you need the vac pump to generate the vacuum to run the servo, without it you would have no servo assistance on the normal foot brake.

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Well done RaDi90Hybrid,

I had a cheap vacuum pump fitted, and after only 7 months the one welch plug popped, fortunately just as I was pulling into a filling station. I managed to modify with a tube and pipe clamp, and limped back to the nearest town, booked into a guest house and had a Wabco couriered to me.

On removal I was shocked to see that normal aluminum pop rivits were used to hold down the head. The Wabco had propper tube rivits that are compressed on both sides.

Many owners replace even the Wabco's rivits with propper bolts and nuts. If I was doing 110/120 km/h on the high way and the welch plug popped, the engine damage would have been servere.

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Hi I'm needing to do this repaire on my disco, my question is do I actually need to take the pump of the block? I think I should have room to drill the rivits out and take the cover off with the pump on the block. Chris.

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If oil is getting into the area of the pop riveted plate then it means oil is getting past the piston, if that is the case then the piston seal is either damaged or worn, in either case replacing the pop rivets with screws or bolts will not resolve the problem, -- replace the pump. I wrote a article on this on WABCO vacuum pumps.

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After an extensive search to track down the source of the oil which was being dumped on the drive under my Disco 300TDi I traced it to a leaking vacuum pump.

First I removed the pump from the side of the block.

Once complete I refitted to the vehicle.

Hi RaDi,

did you set your engine to "top dead centre"?

This job is on my list, and I had this link amongst my favorites:

http://www.the4wdzone.com/vacuumpumpfix.htm

I'd like to understand if setting the "top dead centre" is mandatory or doesn't make any difference...

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The reason that the engine is set at TDC is so that the pump will go on easier - there's a powerful spring in it. I don't bother setting TDC and just push the pump while I get a couple of bolts in the threads. The bolts will then pull the pump all the way on.

Les.

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Thanks Les

^_^

I'll give it a try sooner or later...

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Sorry to hi jack an old thread.

I'm experiencing this leak and stripped the cover off. One of the welch plugs has disintergrated. I thought I could just seal up and leak solved.

However, things don't always leak for no reason and on closer inspection i found traces of oil in the servo pipe - This can't be good - If I just resealed up the oil would still leak up the pipe and into the servo (That can't be good!!)

So just buy a new one as the oil is leaking because the pump is broken. £70 for peace of mind and safety.

Your desicion.

Is oil bad in the servo????

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One of our local fundi's had new stainless steel welch plugs manufactured, the mating surfaces were increased and the OD slightly increased, he also used aitcraft type bolts and nuts to replace the rivits on the head. Works like a charm.

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