question about motors

[86911TLCAB]

I purchased a used motor/window regulator for my E30. Works fine on descent and fine about 3/4 of the way up. Then it begins to slow down and stops about 2 inches from the window closing.

when i test it out of the car, it opens all the way, then closes all the way.

Is this a sign the motor is possibly going bad, or is it likely the cabling is messed up?

any thoughts appreciated before i go return this and seek another...

[roundel]

Sounds like there is some friction in the regulator. Without the motor, can you move it freely through its whole range of motion?

[APKhaos]

There's dirt and crap built up in the window channels. Probably what killed your last motor. Check/clean the window channels. Once you get them clean, hit them liberally with silicon spray.

[arob]

Tito - if it turns out to be the motor, I've got a spare from an E36. Not sure if they're compatible.

Also, as Tony stated - clean out the channels, and check the plastic guides as well.

[86911TLCAB]

The assembly does not allow the cabling to move without the motor (as far as i can tell). butchered another regulator assembly trying to see if i could repair it.
didnt even think about the window channels...will clean up and see if that is the cause...

as i said the thing works fine when disconnected from the window (or outside the car)...i just figured it was the load of the window causing the problem...thanks...try later and hopefully resolve the issue.

[TurboPooch]

Had the same issue on the daughter's VW. Ended up being a frayed cable in the regulator. It would work fine with no load but with the weight/friction of the window plus the frayed cable there was enough total friction to cause the window to stop about 3/4 of the way up....sometimes making it return to the down position. Had to replace the regulator.

[86911TLCAB]

cleaned it up...checked the cabling and it appears ok end to end...and it is working fine...thanks to all for the help.

Follow on question: anyone know of a suitable replacement for the plastic moisture barrier which is locally available?

[cmartin]

I've seen 6mil poly sheet or even a trashbag used.

[86911TLCAB]

ok...so doesnt really have to be anything special...thanks...