Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: cazman on Tuesday,September 13, 2022, 02:36:43 PM
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My door has been sagging again. Even after I thought that I fixed it. I have the Banks door pins, but the root problem is that the upper bushing in the body is worn. Has anyone removed this before? It seems to be "glassed in" snugly. Looking for advice before I try and persuade it out.
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Has anyone tried to sleeve the worn bushing with possibly shim material?
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I wonder how think the bushing wall is and if it will take a bore and sleeve?
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It should be possible to ream the bobbin but getting the new larger hole centered on where it needs to be would be the tricky bit. You would likely have to invent some sort of guide. If you can manage that the bushing should be easy. Red loctite as a retainer.
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Is it worn or is it partially ripped out?
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I remember back in the 80s when I got my car Chris Foulds, a local specialist, gave me a list of things to look for and some potential fixes. In those days the hinge pins would seize in the door and wear away the aluminium body bush so he used to repair them with an insert. I think his were brass and threaded but memory fails after all this time.
A quick scan on SJS and.....
https://www.sjsportscars.com/parts-and-accessories/SJ046B0013.htm (https://www.sjsportscars.com/parts-and-accessories/SJ046B0013.htm)
Brian
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Good suggestions and link.
I guess that I am not sure what I am looking at. Do you think this is the original Bobbin and there is a bushing pressed in to that? Or is the OE Bobbin without a bushing and the SJ bushing is a press in fix?
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Good suggestions and link.
the SJ bushing is a press in fix?
Agreed
The hard part is drilling an accurate hole for it to fit. But I think it is ally.
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The bobbin is aluminum so the hard part will be to drill a perpendicular hole. I suspect that your bobbin is not irretrievably worn so the hole for the sleeve should need to be bigger than the hole you have. If not, that would be a new complication!
I would ask if they recommend using Loctite.
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That bushing also has a step in it at one end. If you don't machine a seat for that, it could get kind of tight to get a wrench in there to tighten the hinge (whichever hinge you have)
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I agree.
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That bushing also has a step in it at one end. If you don't machine a seat for that, it could get kind of tight to get a wrench in there to tighten the hinge (whichever hinge you have)
There is not much extra room with Banks brass hinge replacements.
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When I rebuilt industrial high speed manufacturing equipment we used a reamer with a pilot (line reamer)
to line up holes that a pin or shaft went through.
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If the reamer holder had a tail that fit the lower bobbin, and the pilot at the top as TurboForce described, the reamer would be pretty well lined up to bore a suitable hole.
One thing to consider is that the two hinge bobbins are in fiberglass, not very rigid. It’s not like line boring cam bearing or the bottom end of an engine. There is probably a wide margin that would work just fine.
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I haven't spent much time understanding the details of your problem, but here's a link to a description of how someone went about sleeving the bushings in the body. Maybe it would be of some help (?)
https://www.lotuscorps.org/wp/truing-up-the-body-fit-on-a-1973-lotus-europa-part-2/ (https://www.lotuscorps.org/wp/truing-up-the-body-fit-on-a-1973-lotus-europa-part-2/)
-Vince
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That was a good article!
I was thinking of a similar solution - pulling everything out and epoxying in new bushings at the correct alignment. This method is probably better, as it bores out existing for a sleeve.
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I liked the article too. I know it’s not the area of this thread but when he talks about “fiberglass cloth”, he really means fiberglass mat. I looked closely at his pictures and he definitely does not use cloth.
I think copper is too soft and would use brass or stainless or carbon steel instead.
If the upper bobbin was in good enough shape, I would use that and a 1/2” rod (maybe a hinge pin) to align the tube rather than rely on just tape as he seemed to. That aside, I’ll bet when he finished his car, the body alignment and panel contours were phenomenal! To say they were surely better than the factory fit would be understatement!
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If you haven't done it before, you can reach the top of the upper bobbin by removing the closing plate in the back of the front wheel well. Also the bottom of the lower bobbin, but that's a tighter fit.
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If the existing bobbin is decently solid, I'd leave it. If I recall, the Europa manual has pretty good instructions on how to install a new one.
There's all sorts of thin walled brass bushings available.
Here in the antipodes, common sizes like 1/2 inch are usually available from bearing suppliers. There are also split versions if that helps.
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Well, I don't like the Banks door hinge style as much as I like the original style. After a 3rd attempt at fixing my door sag, I spent real time some time playing around. Here is what I have concluded:
The Banks hinges came with my car and I do not have the directions, but mine rotate against the car-body bobbin. I say against, as the shaft on mine didn't really insert into the bobbin like a shaft in a bushing. More like they ride on it via a chamfer that is machined on the hinge pin. I suppose, as they are brass, they wear in. However, it seems to me that they can wear the bobbin out of round too. That was my situation.
So, I bought the original style in SS from RD Ent. I drilled and bushed the top bobbin with a thin copper plumbing fitting as some have mentioned above. Before I put it in, I ground a flat near the top of the hinge rod and flattened the bushing on one side to match in order to keep the hinge rod from rotating. I can see that it is very easy for the shaft to turn in the bobbin rather than it being stationary. If the rod rotates it will wear the bobbin / bushing causing sag. I made new abrasion washers and installed the set-up the usual way. I am very happy. They seem much better than the Banks. Not knocking Banks, as maybe mine were not installed correctly, causing bobbin wear.
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[...] Before I put it in, I ground a flat near the top of the hinge rod and flattened the bushing on one side to match in order to keep the hinge rod from rotating. I can see that it is very easy for the shaft to turn in the bobbin rather than it being stationary. If the rod rotates it will wear the bobbin / bushing causing sag.
Do you have a pic of what you did to the pin & top bushing?
If I recall, one of our forum members (apologies, can't remember who?) attached an arm to the top most end of the pin which holds the pin stationary in relation to the body. This forces the door bushes to act as the hinge point instead of the bobbin.
As far as I can see, and not having experience with the Banks design, they all suffer the same 'deficiency' in that they allow the pin to rotate in the bobbin.
Happy to be corrected.
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Before I put it in, I ground a flat near the top of the hinge rod and flattened the bushing on one side to match in order to keep the hinge rod from rotating. I can see that it is very easy for the shaft to turn in the bobbin rather than it being stationary. If the rod rotates it will wear the bobbin / bushing causing sag. I made new abrasion washers and installed the set-up the usual way. I am very happy. They seem much better than the Banks. Not knocking Banks, as maybe mine were not installed correctly, causing bobbin wear.
Well done, that is exactly the problem with the original & replacement hinges. The Banks brass ones are better because they don't corrode anything like the steel door bushes, but if they wear and grip the rod then what you've determined is exactly the problem, the soft aluminium (?) bush in the body goes.
Your solution is far neater than the one I did (pin the shaft above the top bush in the cavity behind the front wheel well) but it's going to work equally well. I did my mod shortly after getting the car because mine was also wearing the body bush but fortunately I was friendly with the local specialist who warned me of the consequences.
That would be what, '87, '88 ? I took the doors off for a refresh in 2018 and the steel OEM door bushes still rotated freely on the (still stationary) stainless rod.
You've just made a "fit and forget" mod ;)
Brian
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Here is a picture of how I formed the "D" bushing to match the flat I made in the rod (used a small hammer). This rod was just scrap I had to experiment with. I put a dab of epoxy on the flat O.D. of the bushing to fill the gap and hold the bushing in place inside the bobbin. Hopefully just enough to do the job, but not enough to make it permanent.
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Thanks for the pics, cazman.
That looks simple and effective. 8)
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Just had a thought, cazman.
What keeps the pin from falling down?
Is the lower split pin sufficient?
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Just the cotter pin that goes through the rod. The lower hinge stops it.