Sagging rear end causes

[citybreeze]

I'm trying to work out what is the most likely cause of the rear end sag on my mk3 Spitfire, and work out why it seems to have gotten a whole lot worse.

I've been fixing the car on the driveway for the past few weeks, and had already noticed a bit of a sag on the offside rear compared to the nearside rear.  I could get three fingers between the top of the tyre and wheel arch on the passenger side, but only two on the drivers. 

Today, I took it out for a spin (only acouple of miles) too see how it was running, all felt ok (maybe a little bit 'floaty' at the back end).

Now both tyres are sitting up inside the wheelarches, seems like hardly any damping when I do the bounce test, and both tyres appear toe out (I think that's the term, further out at the bottom than the top, opposite to when I jack it up).

Is this more likely to be a tired leaf spring? Or shock absorbers? Or does it sound like something else has gone wrong?  There was no knocking or bottoming out, even over speed humps. 

 

[Anglefire]

Could be the spacers knackered (Assuming the mk3 is the same as later models?

http://www.triumphspitfire.nl/rearspringpads.html

[Pete Lewis]

to check a lean you need to jack the front end up  centrally and look at the back  then jack the rear end up centrally and look at the front

you would be amazed how many 'lean' are caused by the opposite end of the car to the visual lean 

on top of worn spring pads  have a look at .........

bent antiroll bars are quite often the problem, as are spring pad heights on the front shockers  worth doing a tape measure fitted length of the front springs   two springs are listed  fitted length    green 7.8" +-0.09"   and light blue  7.42" +- 0.09"  both are the same poundage

colour codes are probably long gone 

if the back does a double bounce it sound like the shockers are shot

do your   toe in test to make sure the rears are 0 -3mm toe in

pete

[Gully]

4 hours ago, citybreeze said:

and both tyres appear toe out (I think that's the term, further out at the bottom than the top, opposite to when I jack it up).

 

You're describing negative camber - toe is the difference in alignment between the front and rear facing elements of the tyre.

To eliminate the shocks doing something odd you can always disconnect them and then bounce the rear of the car (not suggesting you drive it like that!). If the lean disappears, you have a shock sticking. However, it does sound as though you have a sagging spring.

Gully

[citybreeze]

I've had a look at the anti-roll bar and it doesn't look obviously bent to me, but one of the mounting brackets is, so I'm guessing it can't be the right shape.  The bushings also look cracked and worn.  

I've been considering the conversion kit from Canleys, for doing the rear spring and bigger anti-roll bar in one go. Does anybody have any positive/negative experiences of using this kit? It's £260 so I'd ideally like to know if it's worth it first.

I don't know how old the shocks are, but from appearance they look very old.  They are a lot cheaper than I was expecting, so I'll probably replace all four.

[Pete Lewis]

If this is a swing spring kit it works well on mk3  spitfire

I think you will find the 7/8" arb was introduced on all in later production as the thin ones tend to gain a set twist..

Pete

[Clive]

As Pete says, the swing spring conversion is good, though a good used spring/arb may be an option? My old MK3 got used parts, back then I paid £10 for everything. Probably a lot more 25 years on.

Re shocks. If you are thinking of the black ones, they are not very good. May be worse than what is fitted. Also check the front seat pan height, they used to be too high making the front of the car sit high and silly. Decent shocks are available, kyb, monroe etc sometimes via eBay, other than that you are on to adjustables. Koni for me....

[dougbgt6]

I have Gaz shocks from the club shop, very good, a dramatic difference. Beware Monroe which I'm told are no longer "Monroe" and made in China, old stock may be alright but how do you know it's the real thing? Same as Lucas.

Doug

[Mad4classics]

7 hours ago, dougbgt6 said:

I have Gaz shocks from the club shop, very good, a dramatic difference. Beware Monroe which I'm told are no longer "Monroe" and made in China, old stock may be alright but how do you know it's the real thing? Same as Lucas.

Doug

Doug,

Didn't know that, I was toying with Monroe aswell. Oh well I'll have to think again.

Thanks

David

 

[Pete Lewis]

it is all down to preferences , how much use and what sort of use you get from your car and wallet

you can go from £80 per car to £350 and more 

club shop is a fair deal on Gaz  but there is a world of difference in quality and price in shockers ....quite shocking 

then with adjustables there is the what to set it at, trial and error

on spax it was reckoned to have the rears on minimum...whats the point  of that ...expensive adjustment seemingly not required

i found on the Vit6 with gaz fronts and spax rears depending on load and road  you were always up a bit down a bit .

drives you mad 

then the adjuster wheel on the gaz filles the detent clicker up with road dirt and you cant turn it without stripping the knob off for a clean

sorry   in a   bar humbug mood

yuo  pays you money and takes a choice

Pete

[Paul H]

58 minutes ago, Mad4classics said:

Doug,

Didn't know that, I was toying with Monroe aswell. Oh well I'll have to think again.

Thanks

David

 

Another vote for Gaz purchased from the club shop as part of suspension conversion for my.mk2 vitesse

Paul

[Clive]

There are kyb adjustables on eBay for approx £80/pr. Kyb are oem on loads of Japanese cars, so buy with a high degree of confidence if you choose them. Non-profit adjustables about £10/pr less, and possibly just as good for most.

 

[citybreeze]

I think I'm going to take the plunge and go for the Canley swing spring conversion then, seems like it'll be worth it in the long run.

As for shocks, I wasn't intending on getting adjustables because as has been said, I just know I'd spend the rest of my life adjusting them...and never getting it just right.

If the standard black ones are poor then I'll probably keep an eye out on eBay for something decent. Those KYBs sound like a good option.

[Pete Lewis]

Thats a sound plan till you get to know the car and decide ìts fine or may be  one  day go nuts and splash the cash

Clives right  Kyb  have good  reputation.

Pete

[ahebron]

Broken leaf?

I had that on my Mk4 a few years ago. Caused by a driving a bit to fast over a bridge and then finding out the other side was slightly washed out. She landed heavily and broke a leaf at the rear.

Adrian

[Pete Lewis]

Cb  you should still do a front rear lift to prove if the lean is front or rear helps focus on anything else you may uncover

Pete

[Badwolf]

I had broken leaf on my mkiv, only to find it was fitted with a leaf spring from a mklll

[hugh]

Knackered spring??

[citybreeze]

Apologies for resurrecting this old thread, but I've only just got around to fitting the rear spring now that the good weather is back.  I bought the Canley swing spring conversion kit, and renewed all the front suspension parts before winter set in (I don't have a garage to work in). 

The spring itself looks pretty straightforward to fit, although I cant see any markings to say which is the front edge, any clues as to where I should be looking?

I'm also fitting a half-inch spacer block.  By the shape of it, it appears like it is supposed to sit directly on top of the diff, and under the spring, is this correct?

I'm concerned that the locating stud on the underside of the bottom leaf will then only locate into the spacer block, and is not long enough to sit in its place on the diff. Is this a problem? 

Many thanks

 

[Pete Lewis]

as far as i remember there is no way round the thoughts seem to be as it always raised a question they marked front for production operators to save them asking all the time 

im sure the eyes are not angled or have any idea what way round they are .

as for a spacer this should have a spigot to drop in the diff hole and a hole to take the spring pin   so both are interconnected all located by the  channel in the diff and the shoulder on the spacer , plus the 4 or 6  studs as well as  the spring centre pin  

you may need longer studs in the diff, 

and yes under the spring , most spacers are quite a snug fit in the diff so may need a check  retorque  after settlement .

Pete

 

[citybreeze]

Cheers Pete

Got it all done this afternoon, the trickiest bit was lining everything up to put the new (longer) studs through.

I've loaded the car up with plenty of weights in the boot and behind the seats, and left a big bag of sand on the drivers seat.  Hopefully it'll settle a bit with that lot in it while I'm away over the weekend.  I'll then retourque everything, and check it again after a few runs.  

 

[Pete Lewis]

You have me well ...puzzled,  i may be wrong here   but........you seem to have a swing spring box with a non swing spring spring.

Hows this to work  you  cant fit the through  bolt , how does this  box   clamp the spring ????

Pete

[Badwolf]

That really looks very much like what I took off my Spitfire (left) and what I was supplied with from Chester and fitted (right). I did have to go back to get the box section and other hardware, but it all works. I must add that a garage fitted it all.

[Clive]

Pete, I think the LH spring is the old mk3 one, and the new spring is a swingspring...

CB, it probably won't settle without it being driven. But The spring eye bolts must be tightened with the weight on the wheels. 

Once it is tightened up, leave the weights in the car for a while, do some hump backed bridges etc to give the suspension a good workout, that usually settles things. Don't gort=get to re-set the rear wheel alignment after (important!)

[Badwolf]

Clive - Thanks for your comments. I doubt that this was done when my spring was replaced (see previous post from 3/07/18). Although settled down well I may go through your instructions just to check.