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Billy, Trainer/Master tech.
Category: UK Car
Satisfied Customers: 3498
Experience:  Trainer - master tech., SAE member
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Allroad suspension compressor problems, I've rebuilt the

Customer Question

Allroad suspension compressor problems, I've rebuilt the compressor with new drying beads, o-rings & piston seal, everything appears good- motor is weak? With my finger over the pipe the motor slows and fails to generate enough.. Desperate to avoid replacing whole unit, can I do any more!?
Submitted: 2 years ago.
Category: UK Car
Expert:  Billy replied 2 years ago.
Hello and Welcome! I'm Billy and i will assist you with your inquiry. Feel free to ask if any further info is needed.
My apologies for the delay, thank you for your patience.
This most likely is a motor issue (mostly the brushes).
However, instead of replacing, i would check: give them a call, as they should be able to rebuild your existing unit at a fraction of the price, and they usually provide 6 months warranty on their work.
Kindly get back to me with your findings, or if further assistance is needed, so we proceed as needed.
Customer: replied 2 years ago.
Thanks will try them tomorrow, is it worth me opening the motor back for a look? Anything obvious to justify sending off- I've resisted this far but if it's brushes I might be able to breath a little life into it?? Appreciate your thoughts, I'm in France so it's going to be a pain to send off however I will if it's my best option.
Expert:  Billy replied 2 years ago.
I would send it over, as it should not take long for them to fix, and there are no brushes this size in the market, so it will be a bit of a headache trying to tackle this yourself.
Get back to me with the results...
Customer: replied 2 years ago.
Hi, I've managed to get hold of the reman company you suggested and they want more money to refurbish my motor than the cost of a new replacement! If this is the only advise you can give me then I don't see any point continuing this thread. I'm planning to open the motor as I have nothing to loose, perhaps rotate the brushes, lubricate the bearing etc- madness to pay £300 + post to rebuild a second hand unit when they are £275 brand new on eBay!
Expert:  Billy replied 2 years ago.
Hello again,
Usually they have good prices, as they rebuild the whole unit. In your case it didn't work probably as you already did most of the work. And i don't think the new units are OE at this price. However, in this case i would definitely advise trying to check and repair the electrical motor as you will be doing.
however first, which brand did you use for the compressor rebuild? and did you check the cylinder (for roughness, scratches etc..)?
do you have the wabco compressor?
and is the motor heating up?
Customer: replied 2 years ago.
Hi, it's a Wabco unit, motor brushes and condition seem ok, motor not heating up and running smoothly, piston chamber getting nice and hot, the round white plastic chamber on the compressor side was inset and I have turned its position to the 'out' set? Air is rushing out, could I have a seized valve chest instead??
Customer: replied 2 years ago.
eBay- genuine Wabco unit, £255.
Expert:  Billy replied 2 years ago.
Let's leave buying a new unit as a last resort, as these unit can and should be fixed. At least one should try first (as you're doing).
If the brushes are good, and motor is not heating up, nor does it have melted plastic in it (as this is usually the case when these motors malfunction), then it should not be a motor issue.
You could have a seized valve, but why did you turn the position on the chamber?
Customer: replied 2 years ago.
I turned the position on the chamber out of ignorance, I can easily turn it back in. I have a good compressor in my garage, can I test the solenoid valve somehow? I had wondered if it may have seized- if I rig up an air line onto the brown pipe, drop the car down of the ramps- fire up and open the compressor, will the car theoretically lift or will the absence of its Wabco bits cause issue. I gather either the compressor or valve chest is faulty but daren't order either without more certainty! Hence my enquiry
Customer: replied 2 years ago.
I think I'm getting there slowly! If I remove the valve unit and connect it on my bench to the compressor can I signal 12v via the block con to operate valves for testing?? Strikes me if I just new the block connector wiring (assume pairs operate different valve solanoids) I could easily test on the bench! Any ideas?
Expert:  Billy replied 2 years ago.
The chamber needs to be turned to original position.
You can give pulses to the solenoids to see if they operate (12V).
I would first rotate the chamber and take it from there...
If you need to test here is the diagram for the three solenoids:
Kindly get back to me with your findings...