Factory Diff Lock Pump Replacment

[datrat]

Hi. I have searched this forum and others and can not find much information on the factory air pumps that lock the diffs.
My chalenger is the XLS 2011 model. The part number for the pump is 3590A011.
The pump runs but is hardly moving any air. Mitsubishi dealer parts dept told me the pump is a vacuum type and quoted $658 trade price.

My questions are:
Is this in fact a vacuum pump as I don't think it is as?
Has anyone ever retro fitted a different type of pump?

Thanks in advance

[bige]

Its a low pressure pump Not a vacuum pump
the steps for checking the pump are from the manual

1.Install the air hose to the differential.
2.Connect a pressure gauge to the air pump discharge outlet nozzle, via the air hose and T-joint.
3.Apply battery voltage to the air pump connector.
4.Measure the time when the pump starts and stops operating, and if it stops within 5 seconds, the pressure switch inside the pump is normal.
5.Measure the pressure 10 - 20 seconds after the pump has stopped.
Standard value: 24.5 - 39 kPa (-30 - 0°C), 24.5 - 34 kPa (0 - 100°C)
6.If the pressure is within the standard value, the release valve inside the pump is normal.
7.Check the pump does not begin operating for 5 minutes after it has stopped.
8.If the inspection for steps 4-7 is normal, the pump is fully operational.

[datrat]

Thanksfor that. I did come across that procedure a few days ago. That's why i thought the guy at mitsubishi was incorrect to say it was a vacuum pump.

I am not going put a test gauge on it, as you can not even feel air moving unless I had wet hands.
The pump seams to be a diaphragm type pump but I don't like my chances being able to disassemble it and fix as its a plastic case.
So I guess I need to find a low pressure type pump that I can do something with.
I hope someone has some ideas.

[old Jack]

Partsque. Part Number 3590A011 $300.
If you pull the pump out there may be a vendor manufacturers name and part number that you can google search, this pump could be used else where and may even be cheaper again.

There is an inlet air filter that can get blocked with mud, if this is blocked the you will not get airflow from the pump. Easy to check, just disconnect both the inlet and outlet hoses to the pump and then run the pump.

OJ.

[datrat]

Yeah its already removed and I have tested on the bench so its not the little rubber breather / filter caps. when tested I can just feel air moving but it will not register anything on a gauge. I did remove the motor to reveal a plastic conrod with a bearing. Its a plastic case that must have the diaphragm and pressure switch in it. I don't think it would survive me cracking it open. There is a square metal plate pressed on one side. I may try to pry that off and see if i can get it apart.
I guess I have nothing to lose
Thanks for the reply's
Cheers

[cookie9]

keen to hear how you go.



What diff symptoms did you have to warrant checking the pump?


cheers

[datrat]

Yeah the symptoms, The when in low range and activating the switch the pump would continually run and the diff lock indicator light would continually flash and not go solid. Also the diff is still open and not locked.
I plan to see if I can get it apart over the weekend.

[datrat]

Well no turning back... Pump is apart.
The rubber seams to have no tension or is stretched. I found it was a bit oily on one side so that may have softened the rubber

[datrat]

What I am thinking of doing is using a pump from an air horn.
They pump between 11.6 - 17.4 Psi and are very cheap.
I would need a pressure switch that will switch it off at about 5Psi. as the factory pump specs are:
24.5 - 39 kPa (-30 - 0°C) 3.5 – 5.6 Psi
24.5 - 34 kPa (0 - 100°C) 3.5 – 4.9 Psi
Im thinking of using an oil pressure switch in the line to switch off the pump.
Most of these switches open between 3 - 7 Psi but I think i can find one that opens between 5-15 Psi.
Does any one know how the diff unlocks?
I think the air get released from the pump.
The pressure switch may incorporate a valve to let the air out?

Any other ideas out there?

[NJV6]

The air gets released from the pump as you say. There is a pressure switch in the pump.

[datrat]

Well still no luck finding an affordable replacement pump. But I have found out that these pumps are used in a few other cars.
Here are the makes and part numbers I have found
Mitsubishi
3590A011 MR453610 MR953484
Suzuki Vitara / XL7
2794065D03TAO 2709465D02 2794065D03 2794065D00

Chevy Tracker 91177534, 91175575

KIA 510303e100

I just thought I would list these as a reference I case others might need to find a replacement.
Cheers

[cookie9]

worth hunting around the wreckers?


do the new pajero sport have the same diff lock pump? could be a cheap option.

[old Jack]

worth hunting around the wreckers?


do the new pajero sport have the same diff lock pump? could be a cheap option.

No, the Pajero Sport has an E Locker fitted.
Low pressure pump is used on the Gen 4 Pajero, Challenger and Triton.

OJ.

[cookie9]

No, the Pajero Sport has an E Locker fitted.
Low pressure pump is used on the Gen 4 Pajero, Challenger and Triton.

OJ.

is it possbile to swap the guts into the PC challenger?

[old Jack]

is it possbile to swap the guts into the PC challenger?

Fitting a Pajero Sport E locker to a Challenger may be possible since it seems to have the same solid axle housing or it should be possible to fit a complete rear disc to disc axle assemble from the Pajero Sport onto the PB/PC Challenger. However most wreckers want about $1800 for the assembly and this is the price you can purchase a Harrop E locker for so there are no real advantages that I can see.

To changeover the diff centre, the spline count on the axles and the axle lengths would have to be identical. You would be able to cross reference part numbers on Partsque if you had the VIN of the donor PS.

OJ.