Jacking up front wheels

[bobspencer]

Is it alright to raise both front wheels off the ground by placing a hydraulic jack under the centre of the front suspension cross member? I am trying to purge the air from the hydraulic steering system.
Also is it ok to put the jack under the rear differential to raise both rear wheels?

[Ronniebiggs]

Bob,

I've used both techniques you mentioned with no problems.

I recommend a block of softwood between the jack and the cross member (unless your jack has a rubber pad). This reduces the likelihood of damage to the beam.

I also strongly recommend substantial chocks behind the wheels, and axle stands under the jacking points for safety. Seals can fail in a trolley jack...doesn't bear thinking about.

Jay

[bobspencer]

Thanks for your reply Ronnie.
The power steering fluid is foaming up out of the reservoir and the steering makes groaning noises when turning. I am hoping that this is severe air entrained in the system that is re-circulating and foaming up.
I will try to disconnect the return pipe at the reservoir to catch the aerated fluid and feed in new fluid till it runs clear and then re-connect. I think that this can be achieved by turning the steering wheel lock to lock with the engine off, and then with the engine on.
It is an Adwest system from a model 340 with the pump driven from the back of the dynamo.
Have you or any other watchers had this problem?
Regards
Bob.

[Ronniebiggs]

Bob,

I've fitted the Adwest system to my Mk2, and have had no problems with it. It has, however, transformed the car! Best upgrade ever.

I would have thought power steering fluid was resistant to foaming; I'm using common or garden ATF in mine. You're right in that cycling the system should remove air, but it would normally come up in comparatively large bubbles (as in brake fluid) rather than foam. Is this a recent problem, or an ongoing one?

Jay

[bobspencer]

Bob,

I've fitted the Adwest system to my Mk2, and have had no problems with it. It has, however, transformed the car! Best upgrade ever.

I would have thought power steering fluid was resistant to foaming; I'm using common or garden ATF in mine. You're right in that cycling the system should remove air, but it would normally come up in comparatively large bubbles (as in brake fluid) rather than foam. Is this a recent problem, or an ongoing one?

Jay

Jay,

I have now tried bleeding the system several times and the fluid is still foaming up from the reservoir.
On investigation I am pretty sure that the is an air leak through the power steering pump seal. Luckily, I have managed to buy a spare which the vendor says works well. I am now passing the problem to my local classic car garage who say that they will look at it in the next couple of weeks - fingers crossed!

Is your Adwest system Silent or does it make a noise on full lock? I have also heard that the system does not self centre too well.

Bob.

[davidr]

Hydraulic power steering systems will have a bypass valve that stops the rack pushing any more when it reached full lock to prevent damage. Could this be the noise you are hearing?

[Ronniebiggs]

Bob,

As David says the system bypasses on full lock - around 1000psi so there will be some noise but in my experience not as much from the Hobourn Eaton roller pump as from vane types such as fitted to Mk 10s. Mine is intermittently a bit groany but the rollers are noticeably worn so probably don't develop full pressure.

Air leak must be on the low pressure side, which I would have thought was somewhere upstream of the pump; check security of clips etc.

Let us know how you get on, good luck with the replacement pump as parts for them (with the exception of seals) seem to be as plentiful as rocking horse manure. The successors to the original manufacturers don't even seem to have drawings available!

Jay