TR4 rear springs

[MikeyB1]

Hello folks, the rear of my car  bottoms out over bumps and potholes easier than I think it should, even though, as I am fully aware, the suspension design is pretty agricultural.  It appears to sit level and pushing on the rear wings doesn't give much vertical movement. However, I suspect that the leaf springs may have lost their temper over the years, can't see any broken leaves, and am contemplating changing them for a pr. of new ones (standard spec.).  Before I shell out £££s I would like to check that the old ones definitely need replacing.  Can anyone give me any dimensions/testing techniques that I can use.  I'm thinking deflection when loaded, eye to eye dimension, distance from top of spring to a line through the eyes.  Any advice would be very welcome including recommendations for supplier.

[Malbaby]

For comments....You could post a pic taken of the side of your car showing the clearance of the wheel to top of wheel arch. 

[Darranh]

Could it be that your lever arm dampers are loose on the chassis and are making a knocking sound when you go over bumps?. Happened to me and a quick tighten up fixed the issue. 

[MikeyB1]

Well how about that?  Just 2 replies, and both from the other side of the world.  Thanks guys

Malbaby...could do as you suggest, but wheel to arch clearace is perfect, already checked that.

Darranh.....it's not just a knock, its a loud bang, as in bump stop thumping hard under the hoop, and has both myself and passenger clenching buttocks (our own, not each others) and exclaiming very loudly as in "sh*t that was a big one!"  Nothing is visibly loose, bent or damaged.

Mike.

[AndyR100]

I was keen to hear thoughts on this one..... my 4 has recently started doing this (bottoming out more and a bit more bouncy) the springs look fine on mine and I was considering shocker replacement, which is a shame because the ones I have were new two years ago

..... Andy 

[iain]

I am with Darren....loose shockers would cause these horrible banging noises. Time for some 3/8” H Tensile cap bolts and nylocs if not already fitted. Cap bolts allowing some serious poundage to be put on the bolts.

Iain

[MikeyB1]

Andy, I would say ignore your shocks.  Their job is to control the bounce that the flexing of the springs induce over bumps.  In theory you could drive a car without shocks except that once you hit a bump the car would continue to bounce up and down long after you hit the bump. Bottoming out is almost always a result of broken or weak springs (or so my extensive research has confirmed).  My quandry is how can I judge if my springs are faulty, I don't want to buy replacements only to find that it's no better.  Mike.

[AndyR100]

it could also be that my weight isn't helping the springs    

in practical terms i have both symptoms - extra bounce and bottoming out... the former being worse than the latter, its a daily-driver so it gets a regular workout.

I agree, you don't want to change just on the off-chance they were past their use-by date, not quite sure of an alternate though.

........ Andy

 

[signalredshaker]

My guess is that your axle is too close to the chassis. I had exactly the same issue when the wheel dropped down after a hump. My solution was to add a lowering pack set from Revington- one or two shims of around 6mm thickness. I added added two to each side and the problem was gone. U bolts were plenty long enough. The car sits lower but the ride is much better- my car has the springs without the aluminium spacer block by the way.

Much better.

James

[Drewmotty]

I found Revingtons 161 lb road/rally springs to be a huge improvement and give a comfortable ride around what passes for a road in Devon and the worst that Ireland can offer without overly testing the bump stops.

Match them with the 450 lb front coils for a nice balanced car.

Its a good idea to post your location so that you can attract some local help......if you're in Devon you can try mine.

Ive found it a great help to strap a Go Pro to the chassis looking at the suspension to see exactly whats happening and when.

Edited January 30, 2020 by Drewmotty

[MikeyB1]

11 minutes ago, signalredshaker said:

My guess is that your axle is too close to the chassis. I had exactly the same issue when the wheel dropped down after a hump. My solution was to add a lowering pack set from Revington- one or two shims of around 6mm thickness. I added added two to each side and the problem was gone. U bolts were plenty long enough. The car sits lower but the ride is much better- my car has the springs without the aluminium spacer block by the way.

Much better.

James

Now you've got me really confused James. If you lower the car, surely the suspension movement is reduced and therefore your'e more likely to bottom out, not less?  I'm not doubting what you say, just can't get it straight in my head!  Mike.

[MikeyB1]

23 minutes ago, Drewmotty said:

I found Revingtons 161 lb road/rally springs to be a huge improvement and give a comfortable ride around what passes for a road in Devon and the worst that Ireland can offer without overly testing the bump stops.

Thanks for the advice Drewmotty, I'll bear that in mind.  Was the handling affected just by fitting uprated rears spring, or did you need to carry out further mods to complement the springs?

[iain]

You won’t see loose shock absorbers, you won’t move them by hand, but having been there and got the T shirt, my money is on a loose shock absorber. They do make a hell of a bang.

[Drewmotty]

My TR4 has the Revington springs, Spax front dampers and polybushes. No anti roll bars or negative camber mods. It drives and rides nicely on the road the stiffer springs having improved the roll rate significantly. We “make good progress” on occasion but it’s generally a usable everyday car. 
My TR3 is a different story :-) :-) :-)

[Drewmotty]

5 minutes ago, iain said:

You won’t see loose shock absorbers, you won’t move them by hand, but having been there and got the T shirt, my money is on a loose shock absorber. They do make a hell of a bang.

I’ve had this on both my cars and it does sound horrific. 

[AndyR100]

I have had loose shocks and agree that they can certainly make a significant noise - although it was a different kind of sound to that of giving the bump-stops some work to do.

they certainly need a some tightening!

..... Andy

[MikeyB1]

OK, I give in to overwhelming opinion.  Tomorrow I promise I'll check the security of the shocks.  If I remember correctly the bolts have already been replaced by cap heads by a previous owner,  but could of course slackened off slightly.  Would be brilliant if that was the problem.....and cheap too.  Will post more tomorrow.  Thanks all.  Mike.

[Hamish]

Fingers crossed 

[signalredshaker]

12 hours ago, MikeyB1 said:

Now you've got me really confused James. If you lower the car, surely the suspension movement is reduced and therefore your'e more likely to bottom out, not less?  I'm not doubting what you say, just can't get it straight in my head!  Mike.

Well, I did think about this - the car is lowered therefore the chassis is lowered. The wheels largely stay where they are- on the ground. That gives a larger gap between the solid axle and the chassis, therefore less chance of the axle dropping onto the top of the chassis rails and banging.

It actually improves the suspension movement and it did work on my car for little cost and effort. The advice about checking the shocker mounting as above is sound as its a very common problem and does make some pretty loud banging.

Good luck!

James

[rcreweread]

Hi guys - surely as the axle fits above the chassis rails, it cant' hit the chassis, and hence make a hell of a din  - it could hit, via the bumpstop on the top of the axle tube ( assuming the bump stop is present) the top of the metal hoop , but I wouldn't have thought that would make a horrendous noise unless the bump stop was missing - my bet also is the lever arms.

This is why lowering the car should improve the clearance whereas logic suggests otherwise

cheers Rich

[Drewmotty]

On my TR3 GoPro on the chassis revealed that snap oversteer was the result of the chassis rising to the bump stop and lifting the inside rear wheel. 
a fatter front arb reduced the effect but introduced a lot of understeer a couple of spacers made from old spring leaves sorted it and the planned rear arb should sort the understeer. 
The point of this reply is that at no time was there any noise or bumping detected from the drivers seat. 

[Mick Forey]

Mike, see this thread for a discussion on rear road springs: replace or repair: 

However, loose dampers on my TR6 made a hell of a noise.

Mick 

Edited January 31, 2020 by Mick Forey

[signalredshaker]

3 hours ago, rcreweread said:

Hi guys - surely as the axle fits above the chassis rails, it cant' hit the chassis, and hence make a hell of a din  - it could hit, via the bumpstop on the top of the axle tube ( assuming the bump stop is present) the top of the metal hoop , but I wouldn't have thought that would make a horrendous noise unless the bump stop was missing - my bet also is the lever arms.

This is why lowering the car should improve the clearance whereas logic suggests otherwise

cheers Rich

Well, if you don't have bump stops in place due to there being little room and you then drop a wheel into a pothole- there's your loud bang. Trust me, it is surprisingly loud- and it can happen when there is a raised bump in the road on the downward travel of the suspension.

Now, if you ask why thee is so little room I don't actually know except that the springs were new, bought in the early '80's from a shop in Birmingham from  Mr C*x. In those days there was no question of whether parts were "right"- it was more a case of getting them at all- and you has to go 100 miles each way to fetch them, there being no 'phone up and deliver them please' service!

It will be interesting to see if MikeyB1's shockers are loose or not in any case.

James

[Hamish]

Videoing shows you quite a lot

 

this is one of my early attempts 

you can see the relative movement via the check hoops. 

 

[MikeyB1]

As per suggestions from several members, I checked the shocker bolts, and sure enough I was able to tighten all 4.  The bumpstops were both still in place ( I replaced them with poly items a couple of years ago) and there is probably around 4" of movement available before the stops contact the limit hoops.  Loaded with my favourite wife, and a bag of compost in the boot we went "bump hunting".  There's still a knock on hitting a large bump/pothole but I think it's not such a crash as before.  I'm beginning to wonder now if I've just been spoilt by driving my wife's Toyota, with it's much more compliant suspension, and that I'm expecting too much from a 58 year old car.  On smoother roads the car rides nicely.  Anyway, when time permits I intend to remove the shocks....perhaps there is an internal fault that is causing the knock, and also investigate the possibility of worn spring bushes/pins etc., as well as soft springs. I'm very grateful for all the advice and suggestions that I have received, thank you all.  Mike.