Electric Vehicle Conversion: Volvo S40 pump to 1984 Jeep CJ-7 stock Saginaw - what fluid??

[4x4 EVC]

I'm at the fluid filling point of my build and now down to hooking up the Volvo S40 electric power steering pump to my stock Saginaw steering knuckle.

A large contingent of Jeep owners call for ATF power steering in the stock set up.

Volvo calls for CHF 202 - I can get that as Pentosin CHF 202 Synthetic Hydraulic Fluid.

Anybody have an option about this - do I give the knuckle what it wants or the pump?

I know it matters but, thoughts?

 

[burbguy82]

Hmm. If it were me, and I had no "knowledge" either way, I would go with ATF. Why? Cost for one, ATF is kind of universal for top off, or "in a bind on the trail", and have used ATF in powersteering before with no issues.
Which component is harder or more expensive to replace? Pump or gear?

Really you have to choose one.

 

[4x4 EVC]

Hmm. If it were me, and I had no "knowledge" either way, I would go with ATF. Why? Cost for one, ATF is kind of universal for top off, or "in a bind on the trail", and have used ATF in powersteering before with no issues.
Which component is harder or more expensive to replace? Pump or gear?

Really you have to choose one.

Okey, well, A.) I'm not on the trail and B.) I'm not comfortable making a Sophie's choice, or for that matter, think I should make that pick.

Silliness aside, yes, ordinarily in an ICE rig, if I was a mile or more from the trail head and something broke, I'd pull out my ATF that I always carry on the trail, of course...

But, A. ) manual transmission so I wouldn't be hauling transmission fluid, B. ) we're talking about and EVC (Electric Vehicle Conversion) so, kinda' in the same vain, no need to haul around extra motor oil or hydraulic oils, mostly due to, you figured it out, an electric motor doesn't need oil (mostly, yes, some do but they use those for cooling also, but no, not me).

Any other thoughts - I don't want to destroy the pump or make the Saginaw leak more then is usual by rotting out the seals prematurely.

 

[burbguy82]

Okey, well, A.) I'm not on the trail and B.) I'm not comfortable making a Sophie's choice, or for that matter, think I should make that pick.

Silliness aside, yes, ordinarily in an ICE rig, if I was a mile or more from the trail head and something broke, I'd pull out my ATF that I always carry on the trail, of course...

But, A. ) manual transmission so I wouldn't be hauling transmission fluid, B. ) we're talking about and EVC (Electric Vehicle Conversion) so, kinda' in the same vain, no need to haul around extra motor oil or hydraulic oils, mostly due to, you figured it out, an electric motor doesn't need oil (mostly, yes, some do but they use those for cooling also, but no, not me).

Any other thoughts - I don't want to destroy the pump or make the Saginaw leak more then is usual by rotting out the seals prematurely.

Ok, just giving my thought, as originally requested. Sounds like you have answered the question all by yourself and are looking for validation of your predisposed position.. Why even ask? Clearly by your answer, you are clearly opposed to ATF.

 

[4x4 EVC]

God, I sounded like a complete **** - sorry, I've been dealing with people that think changing vintage vehicles to EVs - especially Jeeps - is on the level of capital murder - pure sacrilege.

Again - VERY SORRY for the tone!!!

No, I don't know what to do, someone suggested that the steering knuckle is more sensitive then the newer Volvo pump and to feed the knuckle and the pump be ****ed - two in your camp for ATF.

No clear answer.

Sure would like to hear from other voices about the pro's and con's.

 

[MolaKule]

I would use the Pentosin CHF 202 because the additive package is slightly different than for an ATF.

 

[4x4 EVC]

I would use the Pentosin CHF 202 because the additive package is slightly different than for an ATF.

I think that's the problem, it might have stronger additives that might (probably will) eat the seals in the steering knuckle (Saginaw).

Don't know....

 

[MolaKule]

I think that's the problem, it might have stronger additives that might (probably will) eat the seals in the steering knuckle (Saginaw).

Don't know....

What do mean by stronger additives and why would you think that in over 50 years of formulating synthetic oils that it would damage seals?

 

[4x4 EVC]

What do mean by stronger additives and why would you think that in over 50 years of formulating synthetic oils that it would damage seals?

Because the seals for one of the parts was made for use with a certain type of fluid and the other was made with a different one in mind.

ATF and CHF are very different. CHF is what's called for according to many of the links to Volvo sites - I don't have one so I just don't know.

For example, they can't be mixed.

 

[4x4 EVC]

I guess the question becomes this: the Saginaw is cool with ATF, is the Volvo also?

 

[MolaKule]

Because the seals for one of the parts was made for use with a certain type of fluid and the other was made with a different one in mind.

Please explain what seals as most seals are elastomers that have been tested for use with synthetic fluids.

 

[4x4 EVC]

Please explain what seals as most seals are elastomers that have been tested for synthetic fluids.

The Saginaw in my Jeep and about 5 million other Jeeps, were made before there were synthetic fluids (1980's era) - the reason I'm here is because I was hoping someone would have far more experience then I on this mixed set of 60++ year-old Saginaw connected to a 2004-2014 Volvo pump.

What do you think, ATF (general purpose steering fluid)?

 

[meep]

While I don’t know about the seals, my gut sort of wonders if the Volvo pump will be more picky about the fluid than the Saginaw rack. Otoh, the CHF might be a lower viscosity, and you won’t want too thin of a fluid in the rack?? I suspect the CHF would be a better fluid.

What it not superseded by a newer version, CHF 11 or something like that?

 

[4x4 EVC]

While I don’t know about the seals, my gut sort of wonders if the Volvo pump will be more picky about the fluid than the Saginaw rack. Otoh, the CHF might be a lower viscosity, and you won’t want too thin of a fluid in the rack?? I suspect the CHF would be a better fluid.

What it not superseded by a newer version, CHF 11 or something like that?

Didn't even think about the viscosity - interesting, makes sence, you know, at least as a talking point.

I just bought a gallon of the general purpose stuff. If I put it in, I assume it will work but what do you think I should look / listen for - squealing from the pump, if it's working too hard? It could stutter, I guess.

Also, what's the worst thing the can happen - it stutters, not perfect, drain it, try a different bottle of fluid - something like that??

 

[MolaKule]

+

The Saginaw in my Jeep and about 5 million other Jeeps, were made before there were synthetic fluids (1980's era) - the reason I'm here is because I was hoping someone would have far more experience then I on this mixed set of 60++ year-old Saginaw connected to a 2004-2014 Volvo pump.

What do you think, ATF (general purpose steering fluid)?

Since this is mixed set (new/old components) experiment I think it is incumbent upon you to pick a fluid and do the test and then report back the results.

 

[4x4 EVC]

+

Since this is mixed set (new/old components) experiment I think it is incumbent upon you to pick a fluid and do the test and then report back the results.

Yep, that's what I must do.

Okeydokey, out to the Jeep shed, what's the worst thing that could happen.....

 

[meep]

Didn't even think about the viscosity - interesting, makes sence, you know, at least as a talking point.

I just bought a gallon of the general purpose stuff. If I put it in, I assume it will work but what do you think I should look / listen for - squealing from the pump, if it's working too hard? It could stutter, I guess.

Also, what's the worst thing the can happen - it stutters, not perfect, drain it, try a different bottle of fluid - something like that??

Keep an eye on pump temperature when not working the wheel, since the ATF is likely thicker. If the pump isn’t overworking that’s a good sign. Might also consider pulling an amp draw when it’s pumping fluid without steering load. Besides that, watch for leaks, though I imagine the chemistry should be ok, chances are.

 

[4x4 EVC]

Quick update: No leaks but no power either - it was as if I didn't have any power steering.

I can hear it humming and feel a slight vibration in the unit when touched.

Let me do some tests - make sure the signal wire is sending a signal to the unit to turn on. Things like that.

I'll let you know.

 

[meep]

Is it primed? You may need to get fluid in the lines first time, then connect them up.

 

[4x4 EVC]

Is it primed? You may need to get fluid in the lines first time, then connect them up.

No, didn't do that. Quick How To on that?