Technical power-steering pump always on? Ducato 2.8 JTD (MY 2002)

[fucato]

Hey all,
I have some problems with my steering which are related to my strut bearing (which is another story). However while investigating the issue, the mechanic found out that my power-steering pump is always pumping. According to him it is only supposed to pump while steering.
I already found out that if I do a full steering to either side it actually stops pumping.

So I was wondering is this a Fiat specific thing or is there actually something broken?

TIA

 

[corcai]

Hey all,
I have some problems with my steering which are related to my strut bearing (which is another story). However while investigating the issue, the mechanic found out that my power-steering pump is always pumping. According to him it is only supposed to pump while steering.
I already found out that if I do a full steering to either side it actually stops pumping.

So I was wondering is this a Fiat specific thing or is there actually something broken?

TIA

There is no solenoid, switch or other device in the pump to turn it off. When centered the oil circulates without resistance. However when the strut bearings are seized the steering may not self center and thus keep assisting.

Make sure when they replace them that they clean the surface the seals runs on and replace the seals if work or you'll end up with water in there again. I also pack the seal with waterproof grease and remove the excess after its retorqued and turned several times.

 

[fucato]

I have seen on the technical drawings that the pump is directly attached to the fan belt. However as I wrote before when doing a full "turn" (to the stop), there is no pumping in the reservoir. How is this achieved? And isn't it supposed to be that way when straight and no steering?

Make sure when they replace them that they clean the surface the seals runs on and replace the seals if work or you'll end up with water in there again. I also pack the seal with waterproof grease and remove the excess after its retorqued and turned several times.

Which sealing's are referring to, do you have a picture? Thanks!

 

[corcai]

I have seen on the technical drawings that the pump is directly attached to the fan belt. However as I wrote before when doing a full "turn" (to the stop), there is no pumping in the reservoir. How is this achieved?

"connecting cross sections in the cylinder bore enable an overflowing of the oil from the cylinder chamber under high pressure to the return oil chamber separated from it by the piston, just before the end of the stroke. The
pressure drop at the lock stop resulting from this protects the steering pump and the mechanical parts of the steering gear from excessive loads"

And isn't it supposed to be that way when straight and no steering?

When the top strut bearings are rusty, the bottom of the strut moves freely while the top gets stuck, this results in torsion in the spring which pushes against the steering rack effectively turning the rotary valve in the steering rack.

Which sealing's are referring to, do you have a picture? Thanks!

I was talking about the v ring seals (Vollgummi-V-Ringe) for the top strut bearing.

The top strut bearings are unsealed needle roller bearings (Nadellager) and seize easily if there is not a good seal.

The v ring seals against the top spring seat which is usually rusty, this rust can prevent a good seal if not cleaned.

 

[adlarplant]

the power steering pump is always pumping its an open centre design so any oil not used for steering is returned straight back to the reservoir Cheers Adam

 

[fucato]

Thanks for the help guys!
... And while we already changed the subject ;-) ...

So on my ducato probably the left strut bearing and shock has to be replaced.
I'm thinking of doing it myself with the help of a fellow mechanic and in a self-help car workshop.

So far I have already done some works on my ducato, like changing brake pads & discs, wheel bearing and smaller maintenance - but no shocks or strut bearings..

Hence a couple of question:
1. Do you think this is really complicated task or is it quite doable with the instructions from eLearn (which I have)?

2. I know I have to remove the left interior panel to access the strut. However is there then easy access to it or is it still crammed and I should pack some special tools with long reach etc. ?

3. Any extra spare parts I should order/pack which might brake during disassemble? (Like Screws)

 

[corcai]

1 If the workshop has a hydraulic spring compressor it will make it much easier. Otherwise you need really good spring compressors preferably 3. It is easier if you can put two compressors on before you jack the van.

You will need a deep socket to remove the nut on the shock absorber I think its 21mm or 22mm.

The oringinal shocks in mine had no hex or flat to stop the shock from turning when removing / tightening the nut so you need an air ratchet, impact gun really. Something like a chaingrip might work if you're stuck.


2 There is a lot of wiring over the top of the strut but once you loosen the nuts with a large ratchet you can use a small 1/4 ratchet or palm ratchet to spin them off.

3 As I mentioned you should smooth the spring seat surface where the v-ring rubs - if it is rusty or blistered so useful things are:
wire brush
fine sand paper
waterproof grease to pack the seal and prevent rust forming on the spring seat.
thread lock for strut nut

While you have the strut out it is worth checking for and treating / stonechip painting any rust in the strut tower that is inaccessible when the strut is in place.