TR3A Rear Suspension

[John Reilly]

Good day,

Took my rebuild for its long maiden trip last week for a shakedown.

Annoying noise from the rear end. More than a squeak a kind of conch sound when going over bumps. I removed the rear springs shackles and bushes, they are poly, blue in colour and I sprayed them with silicone lubricant, I also sprayed the leaf-springs.

All was quiet for about 5 miles then it started again. Has anyone experienced this?

I'm wondering if it is the leaf-springs (they were new) or the shackle connection. Maybe I'd be better off with the rubber bushes?

Welcome any advice

Thanks

John

 

[stuart]

Make sure the rear shocks are tight.

Stuart.

[Drewmotty]

1 hour ago, stuart said:

 

Make sure the rear shocks are tight.

 

 

…..really tight. I have no paint on the shocker mounting faces and a minimal coat of etch primer on the mounts to avoid fretting and the inevitable clonk. That, with cap head screws and thick machine washers have banished my recurrent shock clonk.  
Those lever arms would have benefited from a four bolt mounting from the outset. 

Edited June 15, 2022 by Drewmotty

[John Reilly]

Thank you both for the advice,

I will check those but it will be next week before I get the opportunity and I will let you know

Regards

John

 

[iain]

2 hours ago, Drewmotty said:

…..really tight. I have no paint on the shocker mounting faces and a minimal coat of etch primer on the mounts to avoid fretting and the inevitable clonk. That, with cap head screws and thick machine washers have banished my recurrent shock clonk.  
Those lever arms would have benefited from a four bolt mounting from the outset. 

Ditto, really tight!

[John Reilly]

Just to be clear, there is no clonk or hard noise, just a sort of progressive groan, sconchy noise. 

Back in the shed, when I press down the rear end I it is quite distinctive, as I was alone I couldn't get under to try and isolate the sound location. Funny though, when I lubricated the shackle bushes and leaf springs, all was silent for a few miles.

J

[Ralph Whitaker]

Could also be the bushes in the shocker vertical links, spray them with silicone too.

Ralph

[Mike Pace]

John,  I just installed the RATCO conversion kit on my TR3B.  It replaces the old lever socks with up to date tube shocks.  I was getting a lot of "jumping" in the rear when I went around a corner or exited off the interstate.  This has corrected that problem and made the handling much better.

Their website is www.rat-co.com and there is also a good write up with pictures from a friend of mine, Paul McBride, who also installed the kit.

Mike

 

[John McCormack]

5 hours ago, Mike Pace said:

John,  I just installed the RATCO conversion kit on my TR3B.  It replaces the old lever socks with up to date tube shocks.  I was getting a lot of "jumping" in the rear when I went around a corner or exited off the interstate.  This has corrected that problem and made the handling much better.

Their website is www.rat-co.com and there is also a good write up with pictures from a friend of mine, Paul McBride, who also installed the kit.

Mike

 

I just had a look at their website. That looks like a neat mod, similar to the ones on my TR6.

 

[John Reilly]

Mike, That is an interesting setup, I will examine it in more detail, I like the cross-brace.

Regards

John

 

[Drewmotty]

Apart from the absence of gas charging what is the advantage of tube shocks over lever arms? As I remember tube conversions were only introduced due to the problems sourcing new lever arms.

Ducks below parapet

Edited June 19, 2022 by Drewmotty

[BlueTR3A-5EKT]

Any one want a set of brackets to fit rear tube shocks?   I think I have a set somewhere that never got fitted.  No shocks though. 

[John Reilly]

I removed the Armstrong units and linkages, car sprung up and down with no noises. The units were fully secure with no signs of movement or fretting.

Links were tight so opened the dampers to find low level of fluid, topped up to within. 5 - 10 mm from top cover. Refitted and tested. Much quieter though there is still the odd "complaint"

I did these units early on in the rebuild, about 2014 so cannot recall exactly what I did (or not do).

Thank you all for the help

Regards

John

PS: I now have another query - new thread

J

[Trumpy3]

Hi

Here is my two bobs worth.

When I was using lever arm shocks, I used 1.5" retaining bolts with good machine washers and a spacer to take up the extra bolt length. I then torqued up the mounting bolts to 50ft/lbs. The theory here was to give the bolts enough length to actually stretch, this stretch maintains the tension much better that short bolts. Never had a problem with my first TR3A.

When I restored/built up my second TR3A I decided to go telescopic from day one. After looking at the rear shocks on my Peugeot 307 I thought that I could follow a similar idea on the TR. After a bit of thought I decided to fabricate a bell crank and mount it on the original shock mount. This right angled bell crank would convert the vertical movement of the axle to horizontal movement. A mono tube gas shock can then be mounted alongside the chassis. I checked with Koni in Germany and they said their adjustable mono tube would do the job.

I fabricated the bits, purchased new shocks, fitted a suitable pin to the chassis to anchor the shock. All fitted as expected. I showed a race car designer/builder my work and he said it was a great idea and did not add any unstrung weight. This was over 20 years ago. I have now done around 100,000 ls including 13 years of track work. still going strong with no repairs/maintenance required.

See the two attached pictures. ( at least I hope so, never done this before)

[Trumpy3]

Just a note.

I mounted the shocks the other way around so the the larger outer cover was towards the front of the car so no debris would be caught.

And yes, they are disc brakes.

[Ralph Whitaker]

What a very clever set up.  How did the ride and handling compare to the original lever arm set up?

Ralph

[Trumpy3]

It is very easy to convert back to lever arm, about 45min so I actually tried them back to back. The result was no difference noted when set up for touring. When the Koni  was adjusted for track, it was a bit harsher. When I was doing track work the only other change to the rear suspension was a panard rod (which I do not think made any difference) and the addition of an extra leaf (3rd shortest) in the springs.

[John Reilly]

Going back to the original post. The strange noise was actually the bump-stop rubber buffers chafing of the check straps. Did a little straining/bending for clearance to obviate contact.

J