TR4/4A TR4 Rear Suspension Upgrades

[Tabcon]

I didn't like the rear suspension in my car at all. Hitting bumps, even small ones, would cause jarring and sometimes I think it was even bottoming out. Handling was not that great either and the worst thing of all, it squeaked.

I took the entire rear suspension system off today, and I'm glad I did. While the restoration on this car was cosmetically great, he didn't really address the small things you couldn't see, like the suspension. The rear shackle pins had been reused and apparently sandblasted with about half of one of the pins gone. All the bushings were rubber and were already starting to deteriorate. One of the shock links cracked in half when I was removing it and the front eye bushings on the leaf springs were almost welded in place. It was a hoot getting them off. The lever shocks were painted, but I think that's about all. One of them barely had any fluid left in it and both were much too easy to push up and down.

Besides all that, the rear end was sitting way too high. Probably from the cheap "competition" rear leaf springs he installed. One of them almost came apart when I removed it.

I'm installing some new quality stuff from Racestorations, but I really don't want to go back to the Flintstone like rear shocks. I've looked at upgraded Armstrong's from Racestorations, but they're very expensive and they are still levers. I've looked at the conversion kits also. One type you have to weld to the axle the other is all bolt on. I've even looked at the adjustable lever shocks now being made...but they are still levers and once the fluid gets warm to hot, the performance falls way off.

Have any of you guys actually installed the a tube shock conversion with adjustable shocks? Do they work? Are there any other options worth considering???

Thanks!

Tab

 

[SCguy]

Tab,

I've been interested in the tube shocks that Moss now offers for the straight axle TRs but I haven't tried them yet. Please let us know what you find out.

 

[TR4nut]

BPNorthwest also carries the conversion. Looks solid. Other easy tweaks are something like poly bushes for the leaf springs, or solid spacers that Joe Alexander sells.

Randy

 

[martx-5]

I just looked at Moss' and BPNW sites, and it appears that the conversion they both sell is only for the TR4A with the IRS.

The original shock mounting for the solid axle cars runs longitudinally with the chassis, whereas the IRS TR4A & TR6 has the shock mounting running perpendicular to the chassis. The IRS cars design is made to take the forces imposed by a conversion, as they are in the same direction. If you put that style onto a solid axle shock mount, the forces are then transfered in the opposite direction for which they were designed.

We saw the results of this at Ratco when we fabricated a conversion for a solid axle car, and within two weeks, the shock mount literally ripped out of the chassis on one side and was cracked on the other.

We repaired the chassis and shock mount, and Tony is working on adding the neccessary bracing to prevent this from happening.

My advice for now is stick with the levers. If they are properly rebuilt and in good shape, they will perform just fine.

 

[TR6BILL]

The IRS cars design is made to take the forces imposed by a conversion, as they are in the same direction.

Tain't necessarily so.



The problem.

The fix, compliments of Tony at RATCO.

Stick with quality rebuilt, uprated Armstrong levers, whether solid axle or IRS (unless you are willing to pay the price.)

 

[Tabcon]

I've done a little more research into this and have decided against the tube shock conversion. One of the things that convinced me was that these conversion units are not approved for racing, nor have I ever seen them used on vintage or production series race cars. Not that I plan on racing this car, but it does say something about the application. I also think the geometry looks weird with these long arms riding in the wheel bay.

Racestorations in the UK rebuilds the original Armstrong units. They are stripped, arms unwelded, rockershaft removed and bodies re-bushed with bronze bushes,shaft machined to take a lipseal so the oil stays in them ( originals have no real seal, just a spash ring), valves modified, pistons and bores matched. They are also matched to the spring rate of the leaf springs they sell. At $250.00 each, they're not cheap, but about the same price as a tube shock conversion with good adjustable gas shocks.

Also, with the addition of the adjustable rear shock links, the system should be able to be fine tuned to a certain extent.

I certainly don't have the qualifications to second guess the Triumph engineers.
Some of their methods may be outdated, but the proof is in the pudding as many of these cars are still not only around, but still being used in competition.

Tab

 

[martx-5]

The IRS cars design is made to take the forces imposed by a conversion, as they are in the same direction.

Tain't necessarily so.

Wow, that's just a real sight. :eeek: I guess with the amount of torque imposed by that long arm sticking up, anything is liable to fail. Although I'd bet that you're conversion lasted more then two weeks. I'm sure a bunch of these conversions have been sold for the IRS cars. Are they all failing like that??

I remember an earlier version of this conversion that also bolted the upper end of the shock arm through the body. I know someone who has had that conversion on his car for years without a problem.

Either way, IRS or not, it's apparent that the current crop of conversions are not suited for these cars.

 

[TR3driver]

Also, with the addition of the adjustable rear shock links, the system should be able to be fine tuned to a certain extent.

Even the original setup can be tuned to some extent. At least most of them had an adjustable operating valve; if not an adjustable valve can be fitted. And the fluid can be changed for more or less damping; within reason.

I recall one of the racers saying he had filled with straight STP, which had worked great for about 2 laps; then blew the shock body apart !

 

[martx-5]

Years ago when I worked at a Saab dealer, we had a customer come in with a 96 wagon. The wagons had lever shocks in the rear just like the TRs. This guy wanted the shocks in the rear as stiff as we could get them, as he said he hauled around alot of weight back there. I filled them up with 90wt gear oil. You could hardly move the back of the car up and down...it was really stiff! He picked up the car and drove off. About a week later he stopped in and said "The shocks are perfect!"

Whatever makes you happy I guess. :laugh:

 

[Moseso]

There is a more local (than UK) rebuilder who does a very good job with the lever shocks. Check World Wide Auto Parts before making your decision. I was very pleased with their work -- and the ease of working with them.

 

[TR4nut]

I just looked at Moss' and BPNW sites, and it appears that the conversion they both sell is only for the TR4A with the IRS.

Just a quick followup on BPNW, I think they recently added conversion kits for the TR3 with wire wheels and TR4.

 

[KVH]

What is this about adjustable rear shock links?

 

[Moseso]

What is this about adjustable rear shock links?

I've never seen any, though I'm sure it could be done. I lowered my rear axle as, part of my modification scheme. I had to "adjust" my shock links by welding an extra inch of length into 'em. Not "adjust<span style="text-decoration: underline">able</span>." "Adjust<span style="text-decoration: underline">ed</span>."

 

[Tabcon]

I emailed and received a response from Peter Caldwell at Worldwide and he sent me a photo of the adjustable Armstrong's.
They do look very promising and are rebuilt to much higher standards than a typical rebuild. I'm seriously considering these also.

Here is a link to the adjustable shock links.

Adjustable Links

Today, I decided to rip everything out, including the rear axle assembly. It's a good thing, because the squeaking I was hearing was a wheel bearing on the passengers side. I figured I might as well pull it out since I wanted to detail the rear end anyway. As one thing usually leads to another, now I've decided to go ahead and rebuild the brakes and install Afin rear drums with some green shoes. I guess I should have stopped there, but since the rear end is out, why not slip in a Quaife LSD.

When will it all end!!!!???

 

[TR3driver]

I had to "adjust" my shock links by welding an extra inch of length into 'em. Not "adjust<span style="text-decoration: underline">able</span>." "Adjust<span style="text-decoration: underline">ed</span>."

They are actually available in different lengths for different applications. I've got some longer ones in the parts bin that I heard are from a MGB.

 

[bgbassplyr]

When will it all end!!!!??? As soon as you finish.....or die.