Power Steering Problem

[noumenon]

I have a power steering problem on my 2002 Boxster S. It has simply stopped working. There were no undue noises or obvious fluid loss.

The first thing I did was to check the fluid level, it was not registering on the dipstick. It took less than 200ml to fill it up to the top (as I expected it to have airlocks and suck some on startup). On start up, nothing happened. Locking the steering a few times each way, I got one or two small bubbles, but nothing big enough to get a level drop.

I then took off the inside access plate to have a better look. Everything looks correct. The belt isn’t slipping and the pulley and inner shaft of the pump are rotating as I’d expect.

On taking the car for a drive with the covers on, but soundproofing removed, I could hear some light clicking noises when steering. I suspect this may just be the relief valve in the pump though. It doesn’t click at idle.

I can’t hear any exhaust/bypass noise or whine at full lock. Though in truth, I never noticed any when the steering was working fully.

The reservoir level does drop a couple of mm when the car is running and rises back a couple of mm when it’s off.

I’m somewhat at a loss as to what the fault is. Anything else I can check or do before taking it to a dealer?

It also has full porsche service histroy and was serviced 2,000 miles ago. Will this cut any water with porsche paying part of the cost of replacing a system that it supposed to last forever? Or am I being far too optimistic and should just take it to a good independent like camtune?

[johnmaddox]

The question is where has the fluid gone. Usually gets past the rack seals and into the bellows at each end of the rack. If bellows in good condition then they can hold the fluid for some time before it leaks out.

You need this diagnosed asap as running the pump dry can ruin the pump and they are ££££.

My 993 lost it's fluid and I removed the rack and got it reconditioned myself and refitted it - £275. OPC wanted £1100 to replace rack.

On the 993 you refill the pump reservoir and on tickover move the steering gently from side to side with the s/wheel to expel the air. (wheels off and axle stands at the front)

Edited by johnmaddox on Tuesday 8th May 13:01

[noumenon]

I got two quotes for new pumps. £100 + postage from a breaker or £150 inc postage to recondition my unit. Of course, fitting will be more.

If it was the rack leaking, wouldn't it either work, or loose lots of fluid?

Do any of the PAS pipes run rearward? There is a small oil weep, which I was assuming was the RMS. Looks dry around the pump and front end of the engine.

Can the gaiters be moved to see if there's fluid in there? Or are they tricky to get to?

Thanks.

Edited by noumenon on Tuesday 8th May 15:24

[andymardle]

The bellows are held by Oetiker ear clamps and can be removed and re-fastened with a pair of pincers. I've only ever done this with the steering rack off the car. I'm only an engineer for the company that supplies Porsche's steering not a technician/mechanic. The power steering snout main seal or housing main seal can fail for a variety of reasons and the hydraulic oil will fill the bellow. Fitting a new snout main seal off the car is straightforward enough but on the car....

[noumenon]

Thanks Andy. I always wondered what that type of clamp was called! I'll have a look at the weekend and see if I can get access while on the car.

If the seals have failed, will the rack damage itself? Or could they run for a time with no fluid?

Thanks again, much appreciated.

[johnmaddox]

I think the rack can run dry for a while but not the pump.

[andymardle]

I really wouldn't want to be driving round in a power steering car with no power steering. You're deflecting a torsion bar within the hydraulic valve under unusual conditions. I have heard of someone driving an old Astra with no oil in his power steering for the last three years but then again, why risk it when a new rack from Porsche dealer cost over a grand last time I checked. That's just for the part.

[noumenon]

Agreed. I'm just wondering what the possibility I need both the pump and rack are!

This weekend will be d-day to find where the fluid loss happened. Prices I have so far are:

Pump £100 scrapyard or £150 to have mine reconditioned.
Rack £400 for reconditioned item from 911 design.

I'm guessing labour shouldn't be too much. I've read the procedure for the pump, which looks simple enough (might even give it a go myself). No idea for the rack, but as there are no driveshafts up front, I'm guessing it's not terribly difficult either. 2-3 hours for each perhaps.

[johnmaddox]

Unfortunately part of the front suspension needs releasing and therefore you also have to build in another £100/£150 for a proper re-alignment. Don't let them tell you they can scribe/paint marks to enable re-assemble accurately -- you can't, not on a Porsche !!

[andymardle]

I can't see how you need both pump and rack. If the pump is pumping oil into and out of the steering rack but there is no assistance then there is only a couple of likely faults with the rack. One of the main seals on the rack has failed or the rack piston ring has failed. Oil inside the bellows indicates a main seal failure. There's a piston fixed to the centre part of the rack internals. It is fitted with an o-ring and ring seal around it's circumferance. That can fail and it means the piston moves but just lets the oil past rather pushing the rack and giving the assistance. You have to strip the whole steering rack to replace the rack piston ring. If it was the snout mail seal that had failed, it has been known for that to be replaced whilst still on other cars in other cases. The snout main seal is the one at the opposite side to the pinion. On a right hand drive car it will be on the nearside.

[noumenon]

I guess I'm preparing for the possibility that a slight weep of a rack seal caused the pump to run dry. I'll gt a torch and have a poke around to see if I can find any fluid.

Are rack seal kits readily available? Are there any specialist tools required? My assumption is that the garage will want to replace rather than repair any fault. Hence I'd like to be able to give them a potentially cheaper alternative.

Thanks again for all the help, very much appreciated.

[johnmaddox]

I would not try fixing the rack - they nearly always fit a reconditioned one. Often parts need changing and pressure testing which is difficult to do off the car. The last thing you want is to spend time doing this and then find it fails as soon as you re-fit it.

The cheapest satisfactory way is to do what I did - remove the rack and send away for re-conditioning.

You must be satisfied with your diagnosis first however.

[noumenon]

Yes, makes sense too. I'm getting quotes of around £100 to recon the pump and around £250 to recon the rack. Sound about right?

[johnmaddox]

That sounds about right price

These people did a good job on my s/rack - still perfect after 12 months

www.westernpowersteering.co.uk/html/racks_porsche.htm

Edited by johnmaddox on Thursday 10th May 17:58

[andymardle]

John's right about checking your diagnosis first. What are you going to do? Remove the pump because it's the cheaper item, send it off for reconditioning, get it back and then refit it? Then if it's still no good, remove the steering rack, then send that off? It just seems a long winded way of going about things. Have you talked to any of the independant Porsche specialists like JZ Machtech?

p.s. The 986 Boxster and the 996 share the same rack just in case yours is fatally wounded and you need to get a replacement. At factory level they share the same drawing number. So they should cost the same.

[noumenon]

I've had a better look today.

Took both the front wheels off and inspected the rack boots. I couldn't see how to get them off. The clip was easy enough to move, but then they still seemed stuck fast. However feeling them, I can't imagine there is 100+ ml of fluid in there. You can move them back and forth with no effort and no noise. There's also no visible fuild anywhere around the front.

Which brings me back to where the fluid went. I can't see anything from around the pump area or top of the engine. However the gearbox is wet with fluid. It's also visible more on the passenger side and looking through the wheel, it can be seen higher up the gearbox than on the drivers side. This is the same side as the pump. Similarly the only fluid under where the car is parked is a few drips every trip from under the rear of the car.

My suspicion is that it is a leaking hydraulic line. Not enough for a complete failure on it's own, but low fluid then caused the pump to run dry and fail. This also fits with the fact that it's not working and not taking/using any more fluid.

I don't really have the tools to get under the car and replace the lines. So off to an indie (camtune) to have it sorted out. Much happier now that I have a better idea of what it is.

Many thanks for all the help, very much appreciated.

[noumenon]

Just booked it in with a specialist. Obviously telephone diagnosis is difficult, but looks like it could indeed be a leaking hydraulic pipe. The specialist has seen low fluidcause the plastic entry/exit connectors to the pump melt resulting in total failure! Now there's something I hadn't thought of. Anyway, once I get the diagnosis/repair, I'll post to let you know what happened.

[noumenon]

The fluid loss could not be explained. However they say that in low mileage cars they have seen it be low without any obvious problem. This does concern me a little as hydraulic fluid doesn't just evaporate, however it's just a case of watching it like a hawk when I get it back. Any loss will obviously need further investigation.

The pump did indeed run dry which caused the reservoir connection to melt and destroy the pump. So the total bill to fix it is:
- one exchange pump
- one new reservoir
- three hours labour
I've asked them to replace the poly belt too. They have to take it off to replace and pump anyway. So it's worth the little extra to push out the next major service (in my case by two more years).

I'm really pleased with the specialist. They know their stuff and the good explanation and fixed reasonable labour time have made the whole experience stress free.

Thansk also for all your help, very much appreciated.

Can't wait to get the car back. It's been two weeks now and I'm itching to get driving again.

[supermono]

noumenon said:

This does concern me a little as hydraulic fluid doesn't just evaporate

Errrr....

SM