Frame Rails, sway bar mounts ripped out : MG Midget Forum : MG Experience Forums : The MG Experience

Frame Rails, sway bar mounts ripped out #1
Acropilot Ty Ty Frisby Newport Coast, CA, USA 1970 MG Midget "Ty's MG"	Posted: March 25, 2012 11:14AM Registered: 1 year ago Posts: 221

I've been putting this one off for a long time now but as the project list gets shorter and shorter I need to start thinking of how I am going to tackle my frame rails where the sway bar attach point is ripped out on one side and bent on the other. I see Moss sells replacement rails for $100 each but that looks like a big/expensive project. I'm leaning towards re-skinning the bottom of the forward portion of the rails to keep time/cost down... any thoughts or suggestions? Is there a source for just the pads with the threaded holes for sway bar attachment or will I need to have these fabricated?

TyFrisby.com

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Re: Frame Rails, sway bar mounts ripped out #2
pixelsmithusa Gerard C San Francisco, USA 1946 Austin 10 1960 Austin-Healey Sprite Bugeye 1960 Morris Minor 1000 Pickup 1960 Morris Minor 1000 Saloon (2-door) 1964 Morris Minor 1000 Saloon (4-door) → more	Posted: March 25, 2012 01:00PM Registered: 2 years ago Posts: 741

Ty,

I think skinning the bottom will be much less work and at the same time, you can use heavier plate stock and/or reinforce the inner side. Fabbing those mounts isn't difficult. Simply get some bar stock and drill and tap the properly spaced holes. If you don't do welding yourself, fins someone who is good with sheet metal. There's some skill involved in the right temperature setting so you don't blow holes/burn it up.

Gerard

http://gerardsgarage.com/

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Re: Frame Rails, sway bar mounts ripped out #3
purpleGT Bud Osbourne Pittsburgh, PA., USA 1974 MG MGB GT "The Grape" 1977 MG MGB	Posted: March 25, 2012 01:53PM Registered: 5 years ago Posts: 2,207

x2 Gerard. Re-skinning the forward section of the frame rails will be pretty basic stuff, for anyone competent in welding autobdy sheet metal.
Another trick you might look into is using longer mounting bolts, which go up through the top of the frame rail, through a doubler on top of the frame rail, with lock nuts on top. It's an old Spridget racer's trick and it sure does work.

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Re: Frame Rails, sway bar mounts ripped out #4
pixelsmithusa Gerard C San Francisco, USA 1946 Austin 10 1960 Austin-Healey Sprite Bugeye 1960 Morris Minor 1000 Pickup 1960 Morris Minor 1000 Saloon (2-door) 1964 Morris Minor 1000 Saloon (4-door) → more	Posted: March 25, 2012 01:56PM Registered: 2 years ago Posts: 741

In reply to # 2022023 by purpleGT x2 Gerard. Re-skinning the forward section of the frame rails will be pretty basic stuff, for anyone competent in welding autobdy sheet metal.
Another trick you might look into is using longer mounting bolts, which go up through the top of the frame rail, through a doubler on top of the frame rail, with lock nuts on top. It's an old Spridget racer's trick and it sure does work.

Nice tip. Hadn't heard that one before.

Gerard

http://gerardsgarage.com/

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Re: Frame Rails, sway bar mounts ripped out #5
Acropilot Ty Ty Frisby Newport Coast, CA, USA 1970 MG Midget "Ty's MG"	Posted: March 25, 2012 02:13PM Registered: 1 year ago Posts: 221

I like the idea of "improving" this area in case I go with an oversized sway bar in the future. I used to weld aircraft tubing and repair exhaust systems in high school shop class using gas but the majority of my welding was arc at a Gold Mine in Alaska where 1/4 stick was the "small stuff". I'll have to practice a bit but my co-worker has a mig machine so I'll plan to re-skin the lower surfaces with un-threaded blocks on the inside to serve as bushings and install the threaded blocks on the top.

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Re: Frame Rails, sway bar mounts ripped out #6
autocomman mark w lost angy, USA 1959 Austin-Healey Sprite Bugeye	Posted: March 25, 2012 02:38PM Registered: 2 years ago Posts: 486

In reply to # 2022049 by Acropilot Ty so I'll plan to re-skin the lower surfaces with un-threaded blocks on the inside to serve as bushings and install the threaded blocks on the top.

Thats exactly what I would do, to my car or a customers

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Re: Frame Rails, sway bar mounts ripped out #7
metalhead Andrew F NSW, Australia 1970 MG Midget MkIII 1977 Mazda 3 1979 Ford F-250	Posted: March 25, 2012 11:55PM Registered: 2 years ago Posts: 412

I would sleeve the bolt holes (add a compression tube) if you are running the bolts through to the other side of the rail. Otherwise over time I would expect the bolts to compress the rail, bending it and loosening the bolts.

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Re: Frame Rails, sway bar mounts ripped out #8
Acropilot Ty Ty Frisby Newport Coast, CA, USA 1970 MG Midget "Ty's MG"	Posted: March 26, 2012 12:06AM Registered: 1 year ago Posts: 221

Good idea.

TyFrisby.com

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Re: Frame Rails, sway bar mounts ripped out #9
purpleGT Bud Osbourne Pittsburgh, PA., USA 1974 MG MGB GT "The Grape" 1977 MG MGB	Posted: March 26, 2012 06:56AM Registered: 5 years ago Posts: 2,207

In reply to # 2022583 by metalhead I would sleeve the bolt holes (add a compression tube) if you are running the bolts through to the other side of the rail. Otherwise over time I would expect the bolts to compress the rail, bending it and loosening the bolts.

This is why you thread the bottom plate and lock nut the top. If you've installed doublers giving sufficient bearing area, you really shouldn't need to use sleeves, although that's certainly not a bad idea by any means. If you fail to thread the lower/bottom plate, you put most of the working load (at least the part of it that's causing the original problem) on the top of the frame rail. The idea is to spread the load out, so that things don't get ripped apart, again.
While it pleases me to think of someone driving a Midget hard enough to create this problem in the first place, I think the sleeves would only be needed under extreme, competition conditions.
Oh, yeah....one more thing: keep in mind that there will be some electrolytic action going on between the doublers and the original frame rail, where they are lapped, especially if air/moisture can get in between them. So, protect the metal accordingly, as local climate dictates.

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Re: Frame Rails, sway bar mounts ripped out #10
Acropilot Ty Ty Frisby Newport Coast, CA, USA 1970 MG Midget "Ty's MG"	Posted: March 26, 2012 10:24AM Registered: 1 year ago Posts: 221

In reply to # 2022675 by purpleGT
This is why you thread the bottom plate and lock nut the top. If you've installed doublers giving sufficient bearing area, you really shouldn't need to use sleeves, although that's certainly not a bad idea by any means. If you fail to thread the lower/bottom plate, you put most of the working load (at least the part of it that's causing the original problem) on the top of the frame rail. The idea is to spread the load out, so that things don't get ripped apart, again.

So the long bolts and holes on top just keep the lower attach point from rocking. I suppose that is all that is required. I may just go stock then seeing as I have a 9/16 bar. I could easily punch the holes on top if I go with a bigger bar in the future.

TyFrisby.com

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Re: Frame Rails, sway bar mounts ripped out #11
purpleGT Bud Osbourne Pittsburgh, PA., USA 1974 MG MGB GT "The Grape" 1977 MG MGB	Posted: March 26, 2012 12:06PM Registered: 5 years ago Posts: 2,207

In reply to # 2022840 by Acropilot Ty

In reply to # 2022675 by purpleGT
This is why you thread the bottom plate and lock nut the top. If you've installed doublers giving sufficient bearing area, you really shouldn't need to use sleeves, although that's certainly not a bad idea by any means. If you fail to thread the lower/bottom plate, you put most of the working load (at least the part of it that's causing the original problem) on the top of the frame rail. The idea is to spread the load out, so that things don't get ripped apart, again.

So the long bolts and holes on top just keep the lower attach point from rocking. I suppose that is all that is required. I may just go stock then seeing as I have a 9/16 bar. I could easily punch the holes on top if I go with a bigger bar in the future.

Well, yes, but in doing so, the newly added stuff on top effectively doubles the strength (more than doubles) the strength of the sway bar mounts. But, yeah, you should be OK with just rebuilding the bottom of the frame rail, if you are running the 9/16" bar. If in doubt, solid weld the bottom plate to the side flanges of the frame rail. That should give you more than enough strength.

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Re: Frame Rails, sway bar mounts ripped out #12
metalhead Andrew F NSW, Australia 1970 MG Midget MkIII 1977 Mazda 3 1979 Ford F-250	Posted: March 26, 2012 09:10PM Registered: 2 years ago Posts: 412

Ah, I follow you now. I agree that doing it that way ought to be strong enough, though personally I think I would still sleeve the holes - more just to satisfy the engineer in me than anything else. I did the same when I built the replacement gearbox crossmember for my Toyota box, despite knowing that with the way I built it and the thick plate steel I used it would never really have been an issue.

As an aside, is this ever much of a problem in a car that's not rusty? Anyone can see that the factory design is not great, but my car is very solid, with no rust whatsoever in these areas and I have been running a 3/4" swaybar for some time without any issues so far... Is this something I should take pre-emptive prevention for, or is it normally only an issue on cars where this area is weakened due to rust or accident damage?

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Re: Frame Rails, sway bar mounts ripped out #13
oldag98 Jeff and Brittany Brackenridge Choctaw, Choctaw, Oklahoma, USA 1965 MG MGB "B" 1976 MG Midget 1500 "Yellow One" 1977 MG Midget 1500 "Dunkirk" 1979 MG Midget 1500 "Parts Car"	Posted: March 26, 2012 09:24PM Registered: 3 years ago Posts: 2,208

I have had a 3/4" inch bar on my car for over a year, with poly bushings, and have had no problems. This is a big thick heavy bar. I did have problems with the rear bar, as the included reinforcement tabs were too small to spread the load on the rear sheet metal causing some slight deformation/creasing. These need to be larger if you run a rear anti-sway bar

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