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MG MGB Technical - Window Winder Mechanism

I have owned a 1968 roadster for a few months. The drivers side window winder has always been stiff but upon trying to close the window recently the effort required resulted in the plastic window winder handle snapping in half. Before I start dismantling the door, does anyone have any idea what the problem could be? Could it just be a case of lubricating the mechanism or something more complex - I'm hoping to avoid removing the window etc to sort it out !
Any suggestions welcome...
M J Ryan

It will likely be a combination of things - worn out window channel inserts, solidified grease on the window pantograph, poorly aligned front and rear channels etc. You will need to take the door lining (card) off and using a shifter to grip the winder have a squiz at whats happening in the door cavity where the winder mechanism sits. If there are no obvious mechanical failures then its back to lubrication and correct alignment of guide channels.
Second hand parts are available all the time on ebay and new channels, handles, inserts etc are available new.
Peter Malkin

There is quite a bit of lost-motion between the winder and the glass, witness how far the handle has to be turned when changing direction before the glass starts to move. This can be used to work out whether the glass is stiff in the channels (are they chewed-up?), or the mechanism is stiff, or both. Wind the glass half way up (or down), then pull up (or push down) the glass until it stops moving, then turn the handle again to catch up with the glass. If the glass is very difficult to move then it is stiff in its channels, it should be able to be pushed up and pulled down within the lost-motion of the regulator quite easily. If the handle is still stiff while turning it to catch up with the glass, then the regulator needs attention. But as I say, it could be both problems.

The regulator is challenging to unbolt, slide out of the channel at the bottom of the glass, be folded up and removed from the hole in the inner door skin, but can be done. Replacement is often more challenging, trying to remember just how you removed it.
PaulH Solihull

I had been putting off replacing the side window rubbers for years. Last Summer, I finally got around to it. During the process, I cleaned and lubricated the window winder mechanisms. The windows now go up and down with almost no effort at all. I couldn't believe the difference some cleaning and lubricating could make. RAY
rjm RAY

...thanks for all the feedback chaps. Have had a look at the mechanism etc now and can see no evidence of problems with channels and so forth and can only assume therefore that the problem lies with the regulator mechanism itself. It is so stiff that even with a pair of grips attached to the half handle that I am left with (after it snapped) it takes a lot of effort to move the glass just a very small distance. Are there any suggestions as to what I can do to improve this without attempting to remove the regulator as, from PaulH's comments, this sounds as if it may be very difficult to do. I cannot see how any effective lubrication can be carried out on the regulator itself without removal.
M J Ryan

"can see no evidence of problems with channels"

Nevertheless, the channels are probably 90% of the trouble. I would consider it a total waste of time and effort to do anything to this wretched mechanism without replacing the channel liners. The fuzzy stuff acts as a lubricant, vs the rubber that is exposed where the fuzzies wear off, which acts as a brake. If the channels are out of adjustment as well, then the glass grabs onto the rubber as it cocks in place, and makes it much worse. Note that there are fuzzies in the bottom of the channels in addition to the sides; If the bottom slide is poorly lubricated, the fore-aft forces cause the glass to stick on the channel bottom.

As Paul said, you should be able to move the glass with one hand while "following" it with the winder, which will enable you to tell if the winder is tight. The glass may move quite freely as you do this, because you are lifting from the center point and there are no F/R or cocking forces generated.

And the damned plastic handles break all the time anyway! There are metal replacements available somewhere.

FR Millmore

Never had a plastic handle break, on this or any other BL car.

My 'challenging' comments were largely jocular, it's actually quite easy to remove the regulator once you have 'folded' it, just remember the orientation as you are taking it out for when you put it back, I didn't and it took me several goes.
PaulH Solihull

There are some pictures at my website. just look for "the MGB wire wheel conversion that turned into a restoration" and go to the restoration and body and doors/windows. They may give you some confidence before you proceed. As Paul says, it isn't very hard to get them apart.

Dave Braun

I had this issue with my 67 GT. The gear mechanism that the handle goes on can, over time, enlarge the opening that the shaft from the handle goes through. When it does, the gear can get on an angle, and binds with the large gear. I was not able to figure out how to fix mine and ended up getting another mechanism.

Not sure if your 68 has the newer mechanism with the flat square on it or the strait post that the MK1 has. If you find you have a similar problem and have the later winder mechanism, I have a set of the newer ones and could send them to you for cost of shipping if they will work.

Bruce Cunha

This thread was discussed between 23/08/2011 and 01/09/2011

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