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GT6 Mk iii rear driver quarter sagging


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Hi All, as per my previous post on tyre pressures and wheel wobble sensation I have been investigating and all so reading the previous post on sagging springs with great interest.

I’ve poked around under the rear suspension and the first thing I have noticed is that the rear drivers corner is sagging - I realised this when I could get a jack under the passenger side just in front of rear wheel but drivers side I could not. It is the drivers side that the wobble feeling comes from.

before I go hunting for a new spring ( notes that springs are scarce at the moment so may well have to wait) is a sagging spring the likeliest cause ? 
 

I can see newish bolts and studs on the spring to diff mount , so it has been replaced recently .

I’d thought the whole rear suspension had been rebuilt but looking closely it is a mix of new bushes and old ones . Not sure why.

anyway , I thought maybe to start with a full bush fitting kit and new shocks and then if no joy with the wheel wobble then go for a new spring replacement. 
 

is there a best place to get a full rear suspension bush replacement kit that comes with everything you need ? 
 

can I ask how easy it is to remove the bush from the spring eye and replace, as from owning old land rovers I know it can be a pain

or am I kidding myself and should just gear up for a full rear rebuild including new spring and embrace the future learning and experience opportunity !

many thanks 

 

jeremy

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I had a similar problem on my Spitfire recently, drivers side rear noticeably lower. Assumed it was the spring but on dismantling found the shock absorber was only extending about 4" from fully closed. It appeared to be fairly new.

After applying quite s lot of force it opened fully and then appeared to work as normal. I put it back on the car and watching closely but so far so good.

Probably an unusual and unique fault on my car but easily checked &, if found, resolved before spending money on something else.

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Your’s is a 72 GT6 as I recall? Later models, after Feb 73 have the new “improved” swing spring and no rotoflex. So there are different springs, be sure to get the right one! For your model you will need the spring lifting tool. £60 from the club shop or higher or borrow one.

Club shop also do Polybush kits, they can be a pain to squeeze in and squeak for a few months. 

But, I would get the spring out and have a look at it before you start replacing everything around it.

Doug

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first thing is prove ite the rear

jack car in the rear centre(not on the diff) and check the front heights

then jack the front and check the rear heights 

low at the back may well be caused by a front issue  especially the bent antiroll bar 

and whilst Doug suggests a spring lifter  that is really only needed on a rotaflex suspension

a swinger is a simple jacking lift to align the eyes 

Pete

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4 hours ago, dellyend1 said:

can I ask how easy it is to remove the bush from the spring eye and replace, as from owning old land rovers I know it can be a pain

Very easy; I did it last week with a small vice and a socket. You'll probably end up pushing the rubber centre and tube out, then go back with a hacksaw and cut the outer metal tube off. Grease the new ones and they'll slide straight in with a vice.

As Cliff says test the shocker; I removed the lower bolt and levered the shock off the upright then extended it fully and recompressed three or four times to get the fluid moving before refitting. 

Check the spring too, if you can see it - I bought a 'NOS very rare late GT6 MK3 rear spring' a few years back and it gave up last month; on removal it wasn't the correct spring at all, having six thin leaves instead of five heavy ones. I never thought to count them having taken the supplier's word that it was the proper and 'very rare' (according to him) item. GT6 rotoflex will have 6 leaves and a free arc height of 116mm.

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1 hour ago, Pete Lewis said:

and whilst Doug suggests a spring lifter  that is really only needed on a rotaflex suspension

Ha! On a previous thread Jeremy says it's a 72 and that makes it a Rotoflex.  :)  

I know this 'cose I got a 73 swing spring, they're easy to do, no lifter required.  But don't try it in a single garage  :wub:

Doug

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Hi All, thank you for all the guidance . In my newness to the GT6 I may have confused myself and all of you or the previous owner has made a fundamental change. My car is 1972 but not rotaflex. I attach a pic of the underside of the rear suspension and I have not got the doughnut on the drive shaft. All thoughts gratefully received as to what i have installed 

37EC2C7F-868F-4D95-93D6-6575B1C5A44E.jpeg

9D76F608-49B8-4F42-B989-D4C7A527DB1B.jpeg

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Hmm,

I wonder what's happened here? 72 would have been Rotoflex originally. 

There's welding required to do the conversion, here's a previous thread about the feasibility of doing it.

Rotoflex to swing spring conversion - Drivetrain & Rear Axle - The Triumph Sports Six Club Forum (tssc.org.uk)

Everything looks suitably rusty, so I wonder if your car's had a complete replacement chassis from a late mk3? 

Good news is you don't need a spring lifter!

Doug

 

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Ok so definitely non-roto. Check the rear spring; is it fixed on top with six studs or four? Six studs is fixed spring and should be eight leaves; swing spring should be five leaves. The 'eyes' on the ends of the spring look quite compact, Spitfire springs which are a common replacement have huge loops. Replacement springs can be hard to source or very pricey, as I recently found.

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43 minutes ago, dellyend1 said:

My car is 1972 but not rotaflex. I attach a pic of the underside of the rear suspension and I have not got the doughnut on the drive shaft. All thoughts gratefully received as to what i have installed 

come on Doug  Keep up    Ha !!

to get a view of what spring  take the cover plate off to expose the top of the diff / how many studs hold the spring down ??  4  or 6

a swinger will only have 4 through a steel box to contain the spring 

Pete

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38 minutes ago, dougbgt6 said:

Hmm,

I wonder what's happened here? 72 would have been Rotoflex originally. 

There's welding required to do the conversion, here's a previous thread about the feasibility of doing it.

Rotoflex to swing spring conversion - Drivetrain & Rear Axle - The Triumph Sports Six Club Forum (tssc.org.uk)

Everything looks suitably rusty, so I wonder if your car's had a complete replacement chassis from a late mk3? 

Good news is you don't need a spring lifter!

Doug

 

Hi Doug, a full replacement chassis is my current theory as I know the previous owner bought it from someone that had carried out a full rebuild. I can’t see any welding . Many thanks . Jeremy

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Now we'll have to see if it's short or long shaft... :)

Less worry than the roto, tho, no need to source good replacement doughnuts unless, as in mine, the shaft shears. Just need to identify the spring and we're on a winner.

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Evening ,

the first thing I would like to say is that I really , really appreciate all the guidance and advice. Thank you for your patience , I’d be stuffed without the support. 
 

ok, so investigating this evening , I have found out:

i. It’s a four stud / bolt spring 

ii. The car still retains the top shock mount in the wheel arch so definitely a conversion ? 
 

iii. The drive shaft length is approx 31 cm from base of cup at wheel end to base of cup at diff end.

iv. I bounced it the car on the rear quarter and it makes an intermittent metal tapping / knocking sound. I’ve attached a small video clip. 
 

v rear driver side height from floor to bottom of sill rail is 17 cm on drivers side and then 19 cm on passenger side.

vi could not see any fractures or cracks in the spring . Noise definitely from drivers side. 
 

a few pics below ,

all pointers and thoughts very welcome. I’m not sure if it would be the spring as the knocking is not consistent with every push down on the car , but maybe that is my wishful thinking. The car seems to settle and is quiet and then after half a dozen pushdown and raises then knocks for the next 3 - 4 ? 
 

many thanks 

jeremy

 

 

 

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Last time I saw a car going like that it was the rear seat springs I was worried about... :)

Definitely swing spring and looks to be five leaf from what I can see.

That brake pipe bracket is bent 90 degrees; you can see how the brake hose is pulled tight to the shock and is rubbing against it, (It's rubbed quite a clean patch on the side) and is a very tight angle round the vertical link. It should be going fore and aft, not sideways, so that the hose goes round the underside of the shocker - comparison photo of my Mk1 attached. It also looks like someone has cut the lower end off that spring eye? Possibly to make it clear the hose and not push it downwards, or is it just the angle of the photo? Second photo from the bottom shows a truncated end just above and to the left of the yellow Goodrich sheathing - this may mean the end eye is bouncing up and down and hitting the upper springs, hence the noise. Second photo shows the way the end should look - GT6 swing spring to left and rusty Spitfire swing spring to right. I suspect that's a Spitfire spring and someone has cut the end off otherwise it would foul the hose.

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on a vitesse swinger conversion you have to add a tight bent short pipe to re route the hose out the way of the flapping sping eye needs a bracket added to the back plate to take the hose route more rearwards away from spring and shocker 

this removes the hose from the middle of the upright or the eye will be whacking the hose 

looks a bit of a conversion without any homework 

Pete

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Jeremy

So a swing spring conversion of a Rotaflex rear end.....now this is starting to make sense.

Obviously condition of the various parts will be paramount and it is quite possible that the conversion has been done with Spitfire bits rather than GT6. You should be able to confirm the identity of the spring by counting and measuring the leaves. A good second hand replacement from the likes of Chic Doig might be an option if required. I don't know whether the vertical links, hubs and brakes are interchangeable, but you could check bay cross referencing part numbers on Canley Classics' excellent website.

One further consideration is the radius arms, which have a different attachment point to the body for Rotaflex/swing spring applications. Has this been addressed in the conversion. Handbrake cable and guides are different as well IIRC. 

We might try and tempt you into a CV converted Rotaflex set up, which is probably the best of both worlds and will reuse your original features.

Ian

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22 minutes ago, Ian Foster said:

Jeremy

So a swing spring conversion of a Rotaflex rear end.....now this is starting to make sense.

Obviously condition of the various parts will be paramount and it is quite possible that the conversion has been done with Spitfire bits rather than GT6. You should be able to confirm the identity of the spring by counting and measuring the leaves. A good second hand replacement from the likes of Chic Doig might be an option if required. I don't know whether the vertical links, hubs and brakes are interchangeable, but you could check bay cross referencing part numbers on Canley Classics' excellent website.

One further consideration is the radius arms, which have a different attachment point to the body for Rotaflex/swing spring applications. Has this been addressed in the conversion. Handbrake cable and guides are different as well IIRC. 

We might try and tempt you into a CV converted Rotaflex set up, which is probably the best of both worlds and will reuse your original features.

Ian

Hi Ian, can I ask what / where the cv converted rotaflex set up is . Is it a full conversion kit ? Can you provide a link as definitely interested in this if I can afford as would like to do it once abs correct . Thanks 

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Dear All, thanks once again for the input. In order to try and avoid you all getting fed up with me , I have decided to tackle this in stages based on budget and avoiding abortive costs etc.

1. I'm going to start with new shocks and bushes. Something (maybe very optimistically) is making me think it may be the shock getting stuck and then releasing or not working properly. The wheel wobble feeling is intermittent and does kind of make sense it could be the spring being released and pinging when driving on the straight. The other rear quarter also feels a lot firmer in that I can't depress it as easily and is certainly not bottoming out or potentially the spring eye making contact with the back of the brake hose. 

2. If phase one is wishful thinking I am then going to take out and replace all bushes and put in new polybushes and bolts / nuts. I would plan to do this anyway as have always done it on previous classic cars owned. 

3. if all else fails obtain new 5 leaf spring. There is currently a wait on arrival or pay uber prices. so I can crack on with phase 1 & 2 in the interim.

4. Sort the brushing of the braided brake hose against the shock. make up the s section of brake pipe and brackets. Needs sorting as plan on running the car by the MOt station when all finished.

5. One day consider the CV shaft conversion. Found it, looks nice, but lots of other things to sort first. 

Many Thanks and will let you know how i get on (Hopefully with a Eureka moment on point of discovery of issue) 

 

Jeremy

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the wheel wobble effect can be a tyre band failure  the thing looks black and round till you drive it then the band takes on a flop/flap lolloping roll

which you cant see until driven   get someone to watch or follow and observe 

drive shaft UJ play a very important roll in the smooth rotation they take a lot of load ,not like a propshaft ,

any knocking on slow corners points to a UJ has had better days or has cup end float

was trying to find the pipe plan for a swing convert but sorry i dont have it now.

have you just disconnected the shocker and tested the bounce/ lean ,  does it improve at all 

Pete

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3 hours ago, dellyend1 said:

I'm going to start with new shocks and bushes

Jeremy

Shocks can usually be appraised off the car. You can pull and push and decide whether they both feel the same.

If there is no obvious play or deterioration in the bushings then this is unlikely to be your problem. Edd China on Wheelers Dealers always gets underneath and gives everything a good waggle with a pry bar. Obviously changing out all the bushes will give you a known starting point and a degree of 'peace of mind'. I have used Superflex polybushes on my Mk2.

Based on what you have said so far, I am suspicious of the spring, so if you are dismantling generally, I would remove and strip down the spring to check for any broken elements. I would also check whether it is the correct spec for the GT6 (Mk3)

Let us know how you get on.

Ian

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Dear All, last post I promise !! 
 

I’m getting confused as to what spring part number I am after as some suppliers quote a spring as being Spitfire Mk4 and GT6 mk3

i know I need a 5 leaf spring but could someone offer up the exact part number at all 

rimmer state is as 159640

I’ve found a Sanderson leaf spring which is this part number. Sanderson have a good reputation with old Land Rover springs. Pic attached . This is quoting the same part number. 
 

thanks 

 

jeremy

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You need 159654, GT6 MK3 spring. Be careful if anyone fobs you off with the Spitfire version, it may fit but as often as not it'll foul on something if it has the large end 'eyes'. Been there.

There are some differences: the GT6 version is 93 lbf/in at the wheel whilst the Spitfire version is 110; Spitfire is 2 x .25" and 3 x .38" leaves and the Gt6 is 2 x .3125" and 3 x .375".

 

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Canleys show part no 159654 to be common for Spit IV late/1500/GT6mk3 late.

Colin's quoted specs for Spit and GT6 suggest there should be differences. Others may be able to confirm from factory WSM (mine doesn't cover late GT6) or other sources.

Jeremy, do you know yet what is currently fitted to your car?

Confusing isn't it. 

Ian 

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