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TR4/4A TR4A solid axle rear leaf spring question

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Popeye

Popeye

Obi Wan
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All,

I am in the process of disassembling my frame and suspension / brakes. The rear springs are mounted differently left-right. I thought there should be a shim on the passenger side, but I found no such shim. The top of the leaf spring has a fairly large "box", for lack of a better term, and I have read on BCF that "The heavy duty/competition rear springs for TR4 did not use a spacer on either side. AFAIK the later leaf springs with a lot more arch and very large aluminum spacers didn't use them either." https://www.britishcarforum.com/bcf/showthread.php?20767-Early-TR4-Rear-Leaf-Springs

However, the different mounting can be seen in the photos below. Passenger side rear link is "down", driver side is "up". Is this correct?? Is this a substitute for the shim?

Note, I have a solid axle TR4A with an IRS frame. I've been told this is not unusual - but cannot verify if someone was trying to make me feel good or if I have an orphan car:smile:.

IMG_7652.jpg IMG_7655.jpg
 
Note - pardon the dark mess of the photos... the body is above the frame and blocks much of the light - making photography difficult. Right now everything is soaking in PB Blaster to help dis-assembly - I could not part the shock from the link, for example.
 
If that is an attempt to adjust the lean -- it seems pretty extreme to me. How did the car look when it had the body on it?

Yeah, lots of 4As got solid axles as (I've heard) US dealers were wary of the additional cost of the IRS. They were also wary of the modern TR4 and thus the TR3B production was done to appease them. Ask any salesman if he wants to market style A, B or C -- and he'll say 'all three'.

FWIW - my TR4 did not have the extra (short) leaf in the passenger side spring but I added it to improve the left/right height match.
 
Mike,
The distance piece ( large aluminum block) on top of the leaf spring is correct for a TR4A with a solid axle. Look at the Moss catalog for a picture of your set up for the TR4A Solid Axle Suspension-page 53. Your frame is very different from a TR4 frame therefore your springs and other attachments are different. Also note in the picture that the springs are mounted on top of the shackle not on the bottom. Again your car's rear suspension is VERY different from a TR4. And in fact is different from a IRS TR4A as well. So you CAN NOT use parts from those cars in this area.
Charley
 
Thanks all. Let's hope it's not the frame. It has been a while since the car was assembled; ten years to be precise, and I don't remember it leaning much one way or the other. There were a few owners in quick succession before I boughb the car (my naivety in purchasing), so I keep expecting a "smoking gun" problem...

I hope to have the chassis completely disassembled this weekend, and I can take some measurements to see how things are.

Which spring is mounted correctly? Basis Charley's reply, it sounds like the passenger side? And, springs are NLA; is it worth replacing with an aftermarket setup?
 
FWIW, Rimmers seems to have the springs available, tho shipping might be prohibitive. I believe the extra spacer was discontinued fairly early in TR4 production, CT23383 according to the factory catalog. Not listed for 4A at all.

If they are in good condition, and reasonable well matched, I'd keep the current springs (after disassembling for cleaning). Replacement springs frequently don't fit well at all (too stiff, ride height too high, etc.) But that shackle turned over suggests some mayhem, meaning one of them might be a TR4 spring or whatever.

I'm not 100% certain, but I think the passenger side arrangement is correct, with the spring going above the bracket on the frame. That is certainly the way the earlier cars are arranged, and the TR4A springs & spacers are fairly similar (tho clearly not the same).

Fig%2020%20Removing%20the%20rear%20spring.jpg~original
 
Terminology is everything. Randall are you referring to " the spacer" being the short piece of spring used to level out the car with only the driver in the car? I assume that to be the case. But the distance piece or spacer on the TR4A solid axle is about is about 4" high and sits on top of the spring.
Charley
 
D'oh! Yes, you're exactly right Charley, and I was using the same term to refer to both of them! My apologies to all.

So, what I meant to say is, the extra pieces of leaf (making the two springs different from each other) were discontinued fairly early in TR4 production. Hadn't noticed before, but according to the SPC they were discontinued at the same time the "re-cambered" (aka high arch) springs and big aluminum distance pieces were introduced. (Now I'm wondering if the distance pieces were different heights.)

And FWIW, the TR4 frame changed at the same time as well. I've not verified it for myself, but I've been told that the later springs can't be used on earlier frames.
 
I hope the spring installation "oddity" is just a mistake made by a previous owner, and was not done to correct a frame anomaly. The car was partially disassembled and re-assembled by previous owners, evidenced by various bits missing, for example the propshaft nuts were just finger tight. I hope someone may have removed and replaced the spring incorrectly.

Using a digital level, I can measure about 1/8" "twist" in the frame, from the rear-most trunk extension to the front of the frame. The frame is supported on jackstands on the back and wheels on the front. Point being, 1/8" is not small, but seems to be within shim thickness variation. Once fully disassembled, I will do some more measurements on the frame.

If the frame checks out as square (are all the dimensions in the workshop manual correct??), and the springs match without any tension (i.e. fully off the car), I suppose I will proceed with restoration and rebuilding. Otherwise... I suppose I could get the frame straightened, or see if someone has a used one they don't need.

Thanks again for the great discussion. i really appreciate listening to all of you, and learning from your experiences!!
 
There is a wealth of knowledge in Pittsburgh via the Western Pa Triumph Association WPTA ( https://wptriumph.org/index2.html ). If you are not a member then consider joining. There is a Tune Up Clinic on April 30 where you can meet and greet a lot of the members who are willing to provide advice. Maybe you already belong but with a list name of Popeye I don't know who you are. Although I now live in OH I still participate in many of the WPTA's functions and have done so since 1980. Come join us if you're not a member.
JVV
 
Thank you Jerry. I am a member - but only as of a few months ago. (Mike Muller is my full name - sorry for the nondescript nature of "Popeye"! It was a high school nickname.) For a variety of reasons, I have not been able to make it to a meeting. I hope to make it to the April 30 meeting, but there is a chance I will be on the road - ugh.
 
Popeye said:
and the springs match without any tension (i.e. fully off the car),
Click to expand...
FWIW, here's a shot of the leaf spring tester I threw together. The air cylinder came from eBay (originally bought for a different project that I haven't gotten around to yet), total cost was under $100. Since the area of the cylinder piston is known, the force can be calculated from the applied air pressure. And the two needle valves (the second one is hanging down, kind of hard to see) made it easy to change the pressure. Leaf springs have a lot of internal friction, so the measured deflection is different depending on whether the spring is going up or down; so I measured both at various points and averaged them.
 
A few of our members have solid axle TR4A's that you could use as a reference. Check out the membership list via the web page, Jim Stoffel and Ken Mikos each have them. Both live in the eastern suburbs
JVV
 
Nice setup Randall ! I usually just put mine on the cement floor and stand on them ! The stiffer of the two goes on the driver's side.
 
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