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GT6 Mk1 very low at rear, identify rear spring and correct fitting?


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My Mk1 GT6 has gradually been getting lower at the rear, in fact when reversing it gets even lower and the mud flaps scrape off the ground. It's a swing-spring conversion on a GT6 MK3 spring and Spax adjustables, set at quite a low setting (maybe 3?)

I quite like the low look but it's now hit a limit where the rear halfshaft is rubbing off the brake hose, again possibly just on reverse but I can't take that chance. The Spax have been on for twenty years now... Paddocks are selling Gaz shocks at a good price - any thoughts? Konis are £60 to £70 more expensive but I want fit and forget, not constant adjustment. All recommendations welcome!

7D6E1A5C-FA31-481C-A1F4-568CE7018692_1_105_c.jpg.d1dfd695b7f0749d5a9a80643b74c397.jpg  7EF02A32-C3E2-470B-94B4-285703968079_1_105_c.jpg.2537bab74357bb1585724eae1f261938.jpg

 

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1 minute ago, Colin Lindsay said:

My Mk1 GT6 has gradually been getting lower at the rear, in fact when reversing it gets even lower and the mud flaps scrape off the ground. It's a swing-spring conversion on a GT6 MK3 spring and Spax adjustables, set at quite a low setting (maybe 3?)

I quite like the low look but it's now hit a limit where the rear halfshaft is rubbing off the brake hose, again possibly just on reverse but I can't take that chance. The Spax have been on for twenty years now... Paddocks are selling Gaz shocks at a good price - any thoughts? Konis are £60 to £70 more expensive but I want fit and forget, not constant adjustment. All recommendations welcome!

7D6E1A5C-FA31-481C-A1F4-568CE7018692_1_105_c.jpg.d1dfd695b7f0749d5a9a80643b74c397.jpg  7EF02A32-C3E2-470B-94B4-285703968079_1_105_c.jpg.2537bab74357bb1585724eae1f261938.jpg

 

I’ve got Gaz on my Vitesse no 2 setting , work well for me

Paul

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I have GAZ from the club shop, one test drive, twiddle and forget about them. 

What state is your spring in? When I bought my car in 1815 I thought it had been lowered, turned out to have a couple of broken leaves. 😱

Doug

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1 hour ago, dougbgt6 said:

I have GAZ from the club shop, one test drive, twiddle and forget about them. 

What state is your spring in? When I bought my car in 1815 I thought it had been lowered, turned out to have a couple of broken leaves. 😱

Doug

Not surprising if it's 206 years old... :)

The spring was a NOS GT6 Mk3 spring from Chic Doig, and I'd like to think it's still in good nick having been greased and protected from new.

The shocks are Spax Gas adjustable. The car doesn't bottom out when driven or make any untoward 'contact' noises at the rear. I suspected the shocks as the halfshaft is able to touch the brake hose, and I'm trying to get it into my head how the spring and the halfshaft can compress down towards each other given that both are fixed points on the vertical link - hence the poor shock got the blame.

Just as well I did decide on a bit of maintenance: not only was one rear trunnion bolt completely unscrewed, right to the end of the threads, but the diff case has two missing bolts, same place on each side... oops... how did THAT happen? That's the same bolt each side, right into the halfshaft housing, and should be the same length as all the others. Why those two, I wonder?

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My money is on the spring sagging. I had a swingspring about 25 years ago, from one of teh big, well regarded suppliers. Sagged in 2 years. Replaced with a used one, no more problems. 

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24 minutes ago, Colin Lindsay said:

Not surprising if it's 206 years old... :)

Yeh, that was a joke it was 1978 so 5 years old. Do what Pete said, disconnect the shocks and you’ve got your answer.

Doug

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22 minutes ago, clive said:

My money is on the spring sagging. I had a swingspring about 25 years ago, from one of teh big, well regarded suppliers. Sagged in 2 years. Replaced with a used one, no more problems. 

I had the exact opposite!! Swing spring from a Spit 1500, used to bottom out all the time. Bought that one from Chic Doig and it cured the bottoming immediately. That's why I'm reluctant to blame the spring, it worked so well! Similarly - I don't want to buy a replacement only to find it's Spitfire again and bottoms out again... I don't think the proper GT6 spring is available any more?

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23 minutes ago, Pete Lewis said:

bolts  HU0808   8 off

so all the same lengths

Pete

New spring washers and threadlock in order, then. I used new washers all round last time, tho.... that is probably the reason the diff was howling at the end of the last run; half the oil has run out through the holes.

I should have the bolts about somewhere.

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I had a similar low riding issue with my swing spring years ago.  Taking the boys to school it would bottom out over a hump back bridge (depending on speed).  I had several inspections underneath and all looked fine.  It wasn't until I lifted the wheel while the car was in the air (simulating its on road set up) that I spotted a hair-line crack.  When I removed the spring it fell to pieces!

As Pete mentioned, it's unlikely to be shocker, the purpose of which is to damp the oscillation on the spring which is suspending the car.  

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12 hours ago, thescrapman said:

Bend thembrackets slightly so the pipe is less likely to.rub n the halfw shaft.

or put a bit of rubber pipemround it as any marks on the braided covering should / will be a MOT fail

That's a priority. I'm paranoid about brakes at the best of times! It's been rubbing on the yellow covering so not yet touched the stainless hose itself, but only one one side of the car too - I wonder if this is due to the weight of the driver? I've got ten days before the first club run, so time to replace a spring if it arrives quickly. 

Any sources for good rear leaf springs? (Not the 'overheads' suppliers who are charging almost £400 for one...) I need 159654 5 leaf, not 159640 Spitfire which fouls the wheel cylinders.

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You could try Owen springs. Or if in good condition, get yours reset (if the steel is any good, many springs are made with poor quality steel, so would not be an option)

Owen springs make them for a few places. Yes, you can get cheap springs. I had one, "normal" price not an ebay special,  from a big retailer, sagged in a weekend, bushes disintegrated and I returned it. In the end I made a spring up starting from an odd rotoflex GT6 spring that was unused but probably 20 years old. Still insure where it came from or why. Then fiddled with some herald leaves. Got something that works with my unusual setup....

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Cheap - no! Good value, yes. There's a difference... :)

Paddocks appear to have the proper spring but might not be in stock, so have e-mailed them. I've also tried GB Springs and will try Owen. Of course the car has been sitting for some time now and this problem only becomes a priority when the club runs are starting again, so I need a fast turnaround.

I never thought about rebuilding. I have four or five Herald and Spitfire springs in the spares pile. Might be worth a look.

It's an eyeopener when I start to think about the timescale; those shocks and that spring have been on the car for almost twenty years. On a modern they'd have been replaced years ago. Maybe it's just due.

 

Edit: Paddocks don't have the spring; Rimmers seem to have but at twice the price. I'll keep looking.

I've just taken the car down off the ramp and the rear brake hose is lying across the rear halfshaft once the car is reversed. The rear spring must have collapsed completely to allow so much movement - new spring required and as the brake hose is scuffed, new hoses and probably shocks required too. I just don't understand how the rear of the car drops so low on reverse and rises again on moving forwards - what's to stop the same problem happening again with £350 of new spring? If I can't identify the reason I can't fix it. Left photo below driving forward, right on reverse. You can see the hose lying parallel to the halfshaft at the bottom; the halfshaft has risen by almost four inches and is now right up where the hose is in the first photo.

71950F8A-CCBE-4BDA-AB2F-4C36F03D3508_1_105_c.jpg.8378466460b14c9f7badcb5ab476b531.jpg  61547CCF-2D58-4EB2-A87F-B1AE3DC2AE53_1_105_c.jpg.b6134aa84f83aa46ec36646a95240b3e.jpg

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  • Colin Lindsay changed the title to GT6 Mk1 very low at rear, identify rear spring and correct fitting?

Ok... as I cannot locate a correct rear spring - part number 159654 which is a 5-leaf spring - I've decided to refit the original 8-leaf fixed spring as a stop-gap. I'm quite amazed to see that I have refurbished it already and salted it away so it's been cleaned, greased and received new bushes in the past. So far so good (except I can't find a spare 6-hole top plate; there should be an awesome collection of them by now in my garage but apparently not.)

Anyway: the original and as I thought correct rear spring has come out. Except: it's 6 leaf, not 5, unless the long bottom leaf doesn't count... and of course it does. So much for the supplier telling me it was extremely rare and charging accordingly way back then. Rotoflex has 6 leaves but is presumably fixed, not swing. Any ideas what the 6-leaf spring may be from? Correct 5 leaf spring in the last photo for comparison.

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Update: replacement spring fitted today, I've gone back to the 8-leaf fixed spring in the hope that it doesn't sag as far. The brake hose was very tight to fit with the axles hanging, but on settling down back onto all four wheels it's as bad as ever.

D9464790-0D13-4338-A7F0-FD36EB1D253F_1_105_c.jpg.36db8fd3498d4f291a9de8b56ca4bab0.jpg

That's a new rear hose in stainless, the old one was quite badly chewed...

E76D5A71-0856-422F-8CAD-20DE09660BA4_1_105_c.jpg.a72f9c1a0ca9976cb2fe92b1b447398c.jpg

So: no idea what to do. If I bend the bracket I risk damaging the metal brake pipes, and besides the brackets are on the correct spot on the chassis. It's only on the one side, too; the other is fine.

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56 minutes ago, Colin Lindsay said:

Update: replacement spring fitted today, I've gone back to the 8-leaf fixed spring in the hope that it doesn't sag as far. The brake hose was very tight to fit with the axles hanging, but on settling down back onto all four wheels it's as bad as ever.

so it still sits as low as it was before?

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No, much higher and the wheels do not move as low when reversing; I've just fettled a few things and hope I've cured it. I wound white masking tape round the axle and drove for fifteen miles including some reversing en route and no marks on the tape at all. The fixed spring is much more comfortable than the swing spring, you hardly feel the bumps at all and I've reset the rear Spax so things seem to be going well. I was able to get the trolley jack in under it on return so it's definitely higher at the rear.

Approx 140 miles to do tomorrow, maybe more, so here's hoping it behaves itself.

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