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TR2/3/3A FRONT SUSPENSION: Rusted lower control arm fulcrum

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M

mgf

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Group: I have a question.

1959 Triumph TR3A TS43919L (Nice Survivor)

FRONT SUSPENSION (ref Bentley Manual FRAME UNIT: Drawing # 265 SIDE VIEW of UNIT

QUESTION:

Is the fulcrum SHAFT for the Lower Control Arms

1. a Continuous THROUGH-Shaft or

2. two (2) STUB-Shafts?

I may want to replace the Passenger's Side forward portion due to rust.

I think the car may have been stored in a company warehouse for much of it's life (64k miles),

but in this particular area, I found surface rust (due to leak in roof?) but no rust at all on the Driver's Side?

I can remove the rust by selective sanding but I'd rather replace this portion of the fulcrum shaft as,

this is the surface upon which the new forward nylon bushing will rotate.

Thanks,

mgf
 
It is a single shaft. Proper alignment is quite a chore on replacement. Given the support to the frame on both sides of each control arm, even rusty it is very strong. The failure point tends to be where the support brackets are welded to the frame. You might want to clean these joints thoroughly to look for cracks and the need to overlay new welds.

Bob
 
bobhustead said:
It is a single shaft. Proper alignment is quite a chore on replacement. Given the support to the frame on both sides of each control arm, even rusty it is very strong. The failure point tends to be where the support brackets are welded to the frame. You might want to clean these joints thoroughly to look for cracks and the need to overlay new welds.

Bob
Click to expand...

I was hoping it was two stub shafts but so much for hoping.

I will proceed with selective sanding & see what I end up with.

Fortunately, it will be a nylon bushing rotating on a metal shaft.

The nylon bushing can be replaced, if required, at some future date.

I will clean & inspect the support bracket welds as you mentioned.

Thanks for your feedback.

mgf
 
Can anyone describe what is involved in either replacing the shaft, or replacing both the bracket and shaft? How is proper alignment obtained?

Dan
 
2long said:
Can anyone describe what is involved in either replacing the shaft, or replacing both the bracket and shaft? How is proper alignment obtained?

Dan
Click to expand...

Dan,

I spent my work lifetime in Engineering/Design creating Design Drawings & approving Detail Shop drawings but mostly Structural vs Mechanical.

If I were going to do it, I would make a drawing using dimensions taken from measurements of an actual unit. I'd use the Bentley Manual drawing ref

I gave in the original post as a starting place. I'd then hire someone with machine shop, fitting/welding skills to machine/fabricate the the shaft & bracket

then weld it in place using a jig (which may be what the factory used?).

There are some knowledgeable, experienced & skilled people on this website, hopefully, someone who has done it will respond.

mgf
 
Dan
As a kid, I had one torn off the frame altogether from roughhousing on dirt roads. I tried to fix it using measurement from reference points. Didn't get it quite right and I don't think you could. Is yours completely off?
Bob
 
Do you realize that there is a replaceable steel sleeve/bush that goes over the shaft that goes all the way through?? That is the steel piece that the nylon bushing rides on. That's the rusty piece that I think your inquiring about. That can be replaced. It just slides over the through shaft. Well, you may have to mess around getting the old ones off. See item #118 in the Moss parts link below...

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29136
 
Replacing the steel sleeve that goes over the shaft can certainly help if the shaft is just a little pitted or worn. But when I redid the suspension on the TR2, the shaft was so pitted and worn that the steel sleeve fit pretty loosely, and the bracketry had some bent flanges. I think the corrosion plus a few curb knocks, or aggressive driving over big ruts, can wrench the shaft around or bend the bracket. The bracket itself is available (I think Roadster Factory) and it has to be welded to the frame. That is the job I was wondering about, or possibly how to assess if just the shaft can be changed. Both sound like major propositions.

Dan
 
The replacement sleeve is a bit longer than the part of the fulcrum on which it rides. It is held still by the pinch of the nut, not its diametric fit to the fulcrum.

Bob
 
So collectively, I got all the info that I needed.

This AM (my 80th Bday) I put some heat to the forward STEEL Bushing & it came right off the through shaft.

The photos are for sp53 (I wasn't ignoring your request) & those who may have a similar experience in the future.

Thanks to all who responded

mgf DSCN4207.jpgDSCN4209.jpgDSCN4208.jpgDSCN4210.jpgDSCN4211.jpgDSCN4212.jpg
 
FWIW, Moss shows a part number for the fulcrum shaft: 031-703. i ran into th same problem on my TR-3A restoration 20+ years ago and just replaced the metal bush. Replacing (and aligning) the shaft would be lots of work, but that part would be an option in case of severe rust or damage.

Jeff
 
I did the same thing to my frame heated them up and much to my surprise they came off. I think they come in some of those suspension rebuild package deal kits, perhaps TRF or maybe Moss. Then I remembered you said you are out there at 80 working on a tr3. Happy birthday=== and I for one am dam glad to hear that.
steve
 
sp53 said:
I did the same thing to my frame heated them up and much to my surprise they came off. I think they come in some of those suspension rebuild package deal kits, perhaps TRF or maybe Moss. Then I remembered you said you are out there at 80 working on a tr3. Happy birthday=== and I for one am dam glad to hear that.
steve
Click to expand...

Steve,

Thanks for the Birthday wish!

I purchased TRF's "Magic Kit" last year (2016) when it was on sale. It includes the subject steel bushing.

Now, Bob has me wondering why he cautioned me that they will not fit?

Still learning at 80!

mgf
 
The plastic element of the new bushes was too big (diameter) so that when you put the plastic on the sleeve and pushed the assembly into the control arm the system was locked up. I had to put the plastic part in a vise and scrape the outside with a razor blade and, after a long while, was able to whittle them down to a desirable snug fit. And a bit of lagniappe from TR3 Driver (Randall)- don't use anti-seize grease on any surface that contacts the plastic bush. It has metallic powder in it that will rapidly abrade the nylon.
Bob
 
Well I never heard that before, I would need some pictures again. I took them off my car with heat and twisting then put the ones from the kit on and everything seems fine, but I am still building this car, but again I have rebuilt many of these over the years and never heard about the nylon bushing being ruined. The old tr2s and early tr3 had rubber down there maybe that is what he is talking about because I think Randall drives a 1956.
steve
 
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