I have a 1996 XJS with the 4.0.

I've had issues with the rear passengers side quarter glass window getting stuck down. A couple of taps by a super long screwdriver and everything works again.

I decided to get at it and open up the motor to see what was going on. What I found looks pessimistic. I am not a motor expert so I'm not sure if what I saw was normal or not.

Please see the pics and notice that the commutator has worn areas. The magnets are also worn at the bottom edges. I decided to pull the magnets out of the housing and swap them upside down, so that the worn areas are now at the top of the housing instead of the bottom.

I used a wire brush and cleaned off the edges of the commutator and the copper area that comes in contact with the brushes. I also cleaned up the brushes.

I lubed everything up with some silicone paste and put it back together.

Did I fix anything? Is the worn area on the commutator indicative of an unrepairable part? Do they make replacement parts for these Bosch motors?

Thanks.

Picture 1 & 2 - Commutator showing worn areas.
Picture 3 - Housing interior looks clean. I flipped the magnets upside down after I took the pics so the worn areas you see are now at the other end of the housing.
Picture 4,5,6 - I brushed off the commutator and the copper area that the brushes contact.
Picture 7 & 8 - brush assembly. Looks good?

 

Replace the brushes.
Is that wear on the armature? is it rubbing?
You may be able to find brushes that be made to work from McMaster carr.
McMaster-Carr

bill

 

The brushes seem good enough. I don't think that's the problem.

If by armature, you mean wear on the silver colored metal parts in the first two pictures, then yes, it seems to have been making contact with the magnets.

 

You need to find the reason the armature is rubbing on the magnets, are they loose ?
if so epoxy them to the case, are the bearings loose?
Also put a few drops of sewing machine oil on the bearings before reassembly.

bill

 

By bearings, do you mean whatever the tip of the armature fits into the housing?

The spindle did seem a bit loose when I put the brushes back on. I didn't think I could service anything that deep in the casing.

You're talking about what's in the very back end of picture #3, right?

 

Yes and there is also one in the front housing If these are worn they need to be replaced they should have very little clearance.
From what I can tell by your photo #3 the bearing looks bad.
You mat be able to find something that could be made to work.
look here http://www.mcmaster.com/#standard-sl...rings/=12fguxq
bill

 

I have had issues with the rear drivers side quarter glass window getting stuck down in my 1991 XJS. A couple of taps by a super long screwdriver and everything works again." Please let me know if your repair fixed this issue.
And now the same problem has started in my 1988 XJS H&E.

 

The front bushing, which is more if a rubber grommet, is in perfect condition. It's definitely the one at the back of the housing that is loose. The spindle doesn't really fit in there as snugly as it needs, and wobbles noticeably. I am now certain that is the culprit.


I will investigate options and report back.


Hypnoguru, tapping the motor housing makes the motor work again, for me, and it lasts for weeks, if not months. I would strongly suggest that you remove the plastic fir fixing (if you have one) that goes in from the quarterglass side. If the glass ever gets stuck in the up position, I would have no idea how you would gain access to the motor with the interior trim in the way.

 

Hi All
I had the dreaded convertible right-hand rear quarterlight motor stop working about a year ago, and just got round to fixing it. My XJS is a UK one, so right hand is drivers side (passenger side in the US).
I checked the relays were working OK and supplying 12v for up/down operation. I removed the side panel trim and tested I was getting 12v at the motor connector, and then tapping the motor housing with a hammer fixed it for a few weeks
It is almost impossible to find replacement XJS convertible regulator or motor parts in the UK, although there is a specialist who manufactures heavy duty replacements, but they are about Ł300 each
I read in one of the threads that these motors are “old school” therefore relatively simple DC motors with a 2 wire connection, so decided to be adventurous and see if I can fix before relieving my wallet of hard earned money

Similar to Vee, I removed the quarterlight regulator mechanism and removed the 2 bolts holding the motor to the regulator, and then gently prised out the nylon housing that holds the brushes. No jaguar or manufacturer part numbers stamped on the motor housing, apart an AC Delco UK label. The brush / commutator arrangement looks slightly different from Vee’s, but that maybe the models were upgraded and I think AC Delco was swapped out to Bosch in 96, but apart from that everything was the same.
First impression was that the windings and brushes had worn on one side more than the other and there was rub marks on one of the magnets.
I found 3 key faults
1) The first issue was at the bottom of the motor housing in the “dome” there is a circular housing for the motor shaft to sit in as in Vee’s picture #3. This was offset slightly (probably built on a Friday !) hence why the motor shaft was offset and rubbing on one side. I am not sure if there is a circular bearing race in there, but by clamping the motor in a vice and using a metal rod I managed to drift the bearing back into a perpendicular position and gave a generous filling of silicone grease
2) Cleaned the magnets, windings and gave them a coat of silicone grease
3) Cleaned the brushes and commutator in the nylon housing with contact cleaner
4) Inserted the windings into the motor housing, and gently replaced the nylon housing back on by pushing the brushes out of the way
5) Held the motor together with some duck tape & clamps, got a spare battery, an in-line fuse and bench tested the motor
6) Absolutely nothing
7) The second issue was I took the nylon brush assembly out and did a connectivity test from the connector leads through to the brushes. The first brush was fine. Then in addition to a diode and capacitor which I believe suppress interference and stop back EMF, I found a 3rd “electronic” device I have never come across before in the shape of a small oblong “copper box”. This device was in line from the incoming cable to the second brush and was open circuit. I came to the conclusion it was a bimetallic thermal cut out built into the motor that had gone wrong. Don’t know why AC Delco built one into the motor as the XJS has separate thermal cut-outs for all windows, but that’s probably because the motor is a mass production item. I soldered a bypass with some auto cable and retested
8) Re-bench tested the motor and ………it worked ……..but rather erratically !!
Thermal cut out?

new washer (in white plasticard)

9) The 3rd issue I found was there was a nylon washer that sits in a circular housing at the top of the nylon brush assembly and holds the motor shaft and windings centrally so they don’t wobble about and touch the magnets. Looking at this washer it had worn away and was allowing the motor to move from side to side and rub against the magnets. Bit of a problem because it was obviously a custom made washer, but I cut a circular disc out of some 1.5mm (60 thou) plasticard, drilled a hole in the centre with the same size as the motor shaft, added some silicone grease.
10) Re-bench tested and hey presto …….absolutely perfect.
I wonder how long it will last??

 

This is brilliant...! Perhaps could and should be made sticky-ish... I've never had a problem nor did I know the unavailability or cost should there be a problem. I hope I never need this BUT if I were to, it would be nice to find it fast.

 

Vee,
Before I retired, I restored scientific instruments.
I can rebuild your motors and give you an estimate before I do any repairs.
The wobble you are getting from the rear is probably because the bearing is designed to adapt to the angle of the shaft.
If you are getting sloppy side to side movement then the bearing needs to be replaced or the shaft is worn.
Have you miked the shaft?
My spares bins are full of different size brushes.
If that's all you need, measure L, W and D and I probably have some.

 

Equiprx,

I would happily send you my motors for repair....when my fix eventually fails, which it hasn’t....yet. I believe I have had one failure since flipping the inside around. (My thread is from 2016)

I believe there are many other people here who would probably love to have you rebuild their rear window motors. That’s a service you might want to advertise somehow. This is a common issue on, at least, the facelift models.

 

Commutator is not worn, The manufacturer ground down that area for dymanic balance.

Polish the copper contact area with steel wool. Would be best to put it in a mini lathe and cut it back until its round.
Make sure the motor turns and runs free in its housing. Repair or replace bushings as necessary.
DO NOT move magnets, they have a pole.

Also replace the brushes and brush springs. As the motor wears, the brushes heat up and the springs loose their force and take a set in a relaxed position thus reducing ampacity to the armature.

 

That's fine, let me know if you have any further problems.
I know there are places on some forums for 'commercial' ads, but I don't think I want to ramp up.
Right now I have too many projects going and don't need any further distractions.