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Advice on rear suspension upgrades & driveshaft boots


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I have been fettling, wire-brushing and refurbing the underside of my TR6.  In checking the suspension, the springs are quite corroded and look old.  It also has the original style shock absorbers, similarly corroded and past their best.  I also found 2 of the boots on the drive shafts were split.  Therefore.....

1) If I'm going to change the springs, should I go to modern shocks as well?

If so, Revington set up looks good - any experiences of that would be great; or are the other set ups with parts that bolt on to the chassis just as good?

2) Whilst I'm doing the suspension, how hard/straightforward is it to take the drive shafts out and replace the rubber boots?

Any preferred/ recommended make of boot?

Thanks

 

tr6 susp.JPG

Edited by Conradski
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Whether to change to a tube shock systems is quite controversial do expect many views. If you do convert (and I am one with a conversion) make sure you get the correct bracketry. The ones that just bolt through  the wheel arch are not really strong enough. 

Changing the rubber boots is reasonably straightforward forward. Undo the inner driveshaft coupling where it bolts to the differential. Slide apart the driveshafts (good idea to mark both halves so they go back together in the same way) sort the boots, renew the grease. Reassemble with new nylon nuts. 

Tim

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Tim no need to mark male and female parts of the driveshaft if you take these apart, as the male and female can only go together in the one place. Both ends have a wider spline that can only go back together in this one place.

 

Getting back to the original question and as Tim states its all about personal taste and just what you expect from the car. Both set ups are a compromise and having tried both for many years (too many actually) I prefer the original set up. I have a TR6 which came into me on Koni's all round and I found the lack of travel and rebound on the rears far too harsh for my tastes, these were whipped off and it now resides on standard rear shocks and it drives just like a TR6 should do, however you will get varying answers from people who think otherwise. My other TR6 is riding on telescopics at present but its about to be changed back to normal as well.

As to the rear driveshafts, take off the rear brake drum, you see 6 locking nuts which hold the driveshaft to the trailing arm so undo these then get further underneath and undo the 6 locking nuts which hold the driveshaft to the diff  and gradually wiggle and shoogle (good Scottish word there) the complete driveshaft out of the trailing arm housing, its really quite simple to do. Then do as Tim states above and reverse the above to install.

Cheers

Alan G

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Alan G, 

Agree most driveshafts have an indexing spline so you can only put them back one way, but got caught out a couple of times by shafts that don't so now mark them as "belt and braces". Conradski, if you do remove the outer part of the driveshaft from the trailing arm, as Alan G suggests, be very careful with the 6 mounting studs/nuts. it is very easy to strip the thread in the trailing arm which means either fitting oversize coarse threaded studs or replacing the thread with helicoil or similar (which requires a special jig to do properly). You may be able to do the job without taking off the outer shaft,  just see how you go.

Tim

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I wouldnt go down the shock in spring route that the Revington kit comprises of as Ive had to weld up a few spring bridges after they have been fitted. I would go back to lever arms and get them rebuilt with a bit of an uplift in performance by these guys https://www.vandcengineering.co.uk/

If your removing drive shafts from the hub, the six nuts that hold the hub to the trailing arm must not be tightened to any more than 16lbs

Stuart.

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A decent telescopic damper bracket (Bastuck), that utilize the original lever arm damper mounting point, including bump stop bracket location, with a pair of Koni dampers (set half way), with some 20% uprated rear road springs (RTR3101R) & Blue comfort TA bushes with transform the handing beyond all recognition on a TR5/6, & give you all the comfort, compliancy and ground clearance needed.

I suspect a few that have converted back to the standard lever arm dampers, may have had their Spax / GAZ / Konis other? set too hard, or have road springs far too stiff.

The above set-up has been fitted to my car since 2009, covered 70k + miles, on track, in Europe, & on endurance events, and tried and tested to perfection !

 

Cheers.

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26 minutes ago, TRTOM2498PI said:

A decent telescopic damper bracket (Bastuck), that utilize the original lever arm damper mounting point, including bump stop bracket location, with a pair of Koni dampers (set half way), with some 20% uprated rear road springs (RTR3101R) & Blue comfort TA bushes with transform the handing beyond all recognition on a TR5/6, & give you all the comfort, compliancy and ground clearance needed.

I suspect a few that have converted back to the standard lever arm dampers, may have had their Spax / GAZ / Konis other? set too hard, or have road springs far too stiff.

The above set-up has been fitted to my car since 2009, covered 70k + miles, on track, in Europe, & on endurance events, and tried and tested to perfection !

 

Cheers.

I think TRTOM has highlighted one of the issues people have with telecopic shock conversions. Often they are set way to hard. My car came with SPAX and even at the softest they were really too hard (had similar problems with SPAX on other cars as well). During my resto I swapped them for Koni and they have enough range on their settings to be set soft enough. Since fitting the car has done 2 RBRRs and 1 10CR and felt good. Interestingly fitting the CV back end really helped the ride (so much my wife noticed).

It is worth remembering that both the Stag and big 6 saloons run tube shocks in place of lever arms on a  similar suspension setup (albeit with a different trailing arm).

Tim

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The gremlin with the conversion that has the shock inside the spring is that because the shock works through a very short range - the forces passed to the mountings at the ends have to be quite high. As Stuart says this part of the diff bridge can crack as a consequence. In theory having the shock inside the spring is sound enough as they work in the same plane/arc.

However the 4A/5/6/Stags and 2000s have the shocks mounted at the end of the trailing arm which gives a greater range of movement so lower force is needed to achieve the same level of damping - simple mechanical advantage.

The Stags had telescopic dampers from the outset mounted in the same place on the trailling arm and through to the top of the wheelarch. The TRs came with lever arms - presumably as a hangover from being a separate chassis.  Over the years there have been many conversions to telescopics. Simple ones having brackets that bolt through the wheelarch (not ideal as the body is less rigid than the monocoque Stag) and more complicated brackets that take the mounting back to the original damper mountings on the chassis. Some also bolt through the wheelarch which perhaps stiffens the body too.  Check the damper does not bottom before hitting the bump stop out or the trailing arm will crack.

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On 1/10/2022 at 7:57 AM, cp25616 said:

As to the rear driveshafts, take off the rear brake drum, you see 6 locking nuts which hold the driveshaft to the trailing arm so undo these then get further underneath and undo the 6 locking nuts which hold the driveshaft to the diff  and gradually wiggle and shoogle (good Scottish word there) the complete driveshaft out of the trailing arm housing, its really quite simple to do. Then do as Tim states above and reverse the above to install.

Cheers

Alan G

Thanks for all the responses and different views from everybody - it is very helpful, even with differing opinions and experiences and is one of the great things about the forum - like a discussion in the pub at the old Wednesday night car club meet but without the colourful language :-).

There will be much shoogling this weekend as I'm going to dismantle the whole o/s/r and see what I find.  It will likely need:

- new drop links

- new springs (will probably go standard but will measure the existing ones first & will replicate as far as possible,...unless of course they have sagged)

- new original lever arm shocks but probably uprated / or have mine refurb'd by Vand C in Bala, which is about 1hr/1 1/4 from me.

+ new nuts, bolts, nylocs and the bushes are shagged too.

Hoping no muckle tools will be needed for this work (a good Stirlingshire word Alan), and everything unbolts with a big bar or the mighty Snap-On impact wrench

Cheers - Conrad

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Conrad,

Sounds like a sane plan.

My experience of doing a number of rear-end rebuilds is that things come undone reasonbly well. Where they don't a cutting disc usually helps.  More of a concern is if you find fractures under the diff pins that need welding or the outriggers on the chassis are too corroded and/or the mounting brackets have cracked.

All are solvable but welding new diff pins or chassis outriggers with the body on is challenging.

(there are some details of when I did similar here)

Fingers crossed

Tim

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I've no intention of changing my shocks any time soon, but just curious. How do you go about  setting up adjustable ones; setting up for comfort I can see but how do you adjust for handling and road holding without access to a track? Do telescopics give any material improvement over lever arms, or are people just comparing with old and worn lever arms? What about altering the damping rates of lever arms with different valves? I have seen adjustable Armstrong lever arms somewhere too.

Mike.

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1 hour ago, michaelfinnis said:

I've no intention of changing my shocks any time soon, but just curious. How do you go about  setting up adjustable ones; setting up for comfort I can see but how do you adjust for handling and road holding without access to a track? Do telescopics give any material improvement over lever arms, or are people just comparing with old and worn lever arms? What about altering the damping rates of lever arms with different valves? I have seen adjustable Armstrong lever arms somewhere too.

Mike.

Assessing what is better is a very personal thing. It also depends on a lot of other parameters (springs, tyres, bushes etc). Adjustment is in your view a bit if trial and error. 

Tim

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On 1/10/2022 at 2:31 PM, ed_h said:

I've never properly understood the problem that tube shock conversions claim to solve. 

Ed

The problem was Ed, that going back twenty or thirty years, one couldn't get replacement lever arms except by handing over half the national debt and Koni's had a much better reputation, so there was little choice for the average impecunious TR owner even with the added cost of conversion brackets.

Jerry

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1 hour ago, jerrytr5 said:

The problem was Ed, that going back twenty or thirty years, one couldn't get replacement lever arms except by handing over half the national debt and Koni's had a much better reputation, so there was little choice for the average impecunious TR owner even with the added cost of conversion brackets.

Jerry

So, the conversions weren't better, just cheaper?  Today, I don't think they are cheaper.

Many of the ads imply some performance benefit.

Ed

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Think the only performance benefit is the ease of adjustment. When I did my swap the quality of lever arm rebuilds was questionable. Now I might have made a different choice maybe

Tim

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11 hours ago, jerrytr5 said:

The problem was Ed, that going back twenty or thirty years, one couldn't get replacement lever arms except by handing over half the national debt and Koni's had a much better reputation, so there was little choice for the average impecunious TR owner even with the added cost of conversion brackets.

Jerry

Agree - IMHO  the handling of the TR with the lever arms is very good - of all the things that could be upgraded on a TR that wouldn't make my list...

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11 hours ago, jerrytr5 said:

The problem was Ed, that going back twenty or thirty years, one couldn't get replacement lever arms except by handing over half the national debt and Koni's had a much better reputation, so there was little choice for the average impecunious TR owner even with the added cost of conversion brackets.

Jerry

Correct plus there was a lot of memories of stuff like the A60`s etc bouncing down the road and TR6 dragging their silencers over every bump.

Stuart.

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A few years back I thought it would be fun going back to lever arms as I missed the nose in the air on take off however the dragging of the silencer on the ground and over bumps wasn't as I remembered it,. Maybe a case of course of me just getting old so it was back to the Spax and TR Bitz brackets with no regrets whatsoever. I might add that the lever arms were brand you, not recons, and that the rest of the suspension had been rebuilt a few years before with new bushes and springs. 

Derek

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3 minutes ago, saffrontr said:

A few years back I thought it would be fun going back to lever arms as I missed the nose in the air on take off however the dragging of the silencer on the ground and over bumps wasn't as I remembered it,. Maybe a case of course of me just getting old so it was back to the Spax and TR Bitz brackets with no regrets whatsoever. I might add that the lever arms were brand you, not recons, and that the rest of the suspension had been rebuilt a few years before with new bushes and springs. 

Derek

Standard new lever arms are too soft, if you get the uprated ones then they react much better and give you every bit as good a ride as tube type.

Stuart.

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I prefer mine to be on levers, its just so much better. Had enough of Spax or whatever, if I eased my ones off anymore then it starts to pogo so next job on Saffie will be to return to levers as on my other 6... way better.

Alan G

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1 hour ago, Andy Moltu said:

Do many modern cars use lever arm dampers?

 

Mr Mcphersons strut  which includes spring and shock absorbers has claimed the field I think.

Mick Richards

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Er…. I’d be more interested in the age of the rear hubs. They do on occasion depart company with the car usually at the most inopportune moment.

The best thing I did was to replace the drive shafts with CV jointed shafts. New springs, poly bush the trailing arms, and overhaul the lever arms with slightly uprated valving!

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