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GT6 MK3 Rotoflex Shock Conversion


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Hi All,

 

You may be aware of an option to convert the original shock mounts on a Rotoflex GT6 to attach to the Chassis instead of the wheel arch.

 

The club shop sells a conversion kit consisting of two GAZ shock absorbers and two extension brackets for the chassis to reach out so the shock absorber doesn't interfere with the Rotoflex unit.

 

I have fitted this kit on my GT6 and am having trouble with it. Every now and then the shock absorbers bottom out on their internal stops.

 

I spoke to Garth from the shop a while ago about the situation and he confirmed that the shock absorbers were the correct spec for the car. I then went to Owens Springs and had a brand new rear spring made for the car, this has dramatically improved the problem but it hasn't gone completely.

 

The only thing I don't have on my car are rubber bump stops on the back, could this be the problem? There just doesn't seem to be much travel on the suspension...

 

What I want to know is does anyone else have any experience of this problem at all? Or any advice?

 

Thanks in advance.

 

Henry

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Henry

 

I have done a similar conversion on my Vitesse Mk2 but using Koni 80-1717 Telescopic Dampers (See Koni Rear Damper Thread in this section).

 

These dampers are orginal fitment for the front of Classsic Mini's, but I have been advised by several people on Club Triumph that they are the correct open (296mm) and closed (218mm) lengths to suit the Rotoflex suspension.  

 

I have yet to travel with two people in the back (4 in Total) to see if the suspension bottoms, but with only two people in the car, no problems :)

 

On the Mk2 Vitesse there is a Suspension Bumpstop for the spring eye to hit each side on the Wheelarch, not sure if you should have these on the Rotoflex GT6 though? 

 

It certainly sounds like the suspension is bottoming on the internal Damper stops?

 

Do you know what the open and closed length is on the GAZ Dampers?

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Henry

 

Just had a look on the Canley Classics site and you should have a bumpstop part number 150583 fitted each side, presumably on the inner wheelarch.

 

If you do have these fitted, you could try putting a blob of white grease on the bumpstop and see if it gets transfered to the relevant part of the spring on full travel, if it doesn't then it will confirm the Dampers are bottoming before giving you full suspension travel, so they must be the wrong closed length :(  

 

I've had no end of trouble with my Vitesse because of a weak Reproduction spring which was far to soft, I've refurbished an original, good condition spring and seem to have solved the bottoming out with my Vitesse, although I haven't had four people in the Car yet? :huh:   

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Hi Gary,

 

Thanks for the response. I am aware I'm supposed to have a bump stop fitted but have heavily modified the underside of the car during rebuild so there is nowhere for them to go. Also, it never had them fitted before and didn't have the problem. having said that, I think I will try it, I'll strap a couple to the spring and see what happens, if it works I'll make a permanent solution, and of course keep you all informed. 

 

Henry

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Henry

 

The Open & Closed lengths of the Dampers are the important bit, can you find out via Garth or GAZ what this is? 

 

I know by listening to several posts on Club Triumph that the standard Koni 80-1389 Dampers recommended for the standard Swing Axle Herald/Vitesse suspension are not suitable for Rotoflex suspension. 

 

Hope you get it sorted.

 

Regards

 

Gary

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I have the similar conversion from Moss on may GT6 MK3 and opted for Koni dampers, although by far the most expensive they are great dampers and everyone I know who uses them swear by them, mainly as they seem to vastly outlast the others from Gaz, Spax, Avo etc.Like anything, you get what you pay for in terms of quality and dampers are no exception.

 

I also have the issue of no bump stops fitted having removed one of the redundnat wheelarch shock mounts that had corroded. The otehr one is just about to come off too, no point in keeping them if you use the shock conbversion as it's just another rust trap. However using Koni rear shocks supplied by MOSS with the kit I have no bottoming out isssues even during pretty spirited driving, only on very bumpy (offroad) situations which I can live with as the shocks have uinternal bumpstops anyway.

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  • 2 weeks later...

Henry

I've come a bit late to this thread but thought a reply worthwhile. I fitted the chassis brackets for exactly the same reason as Cookie.
My wife was driving the GT6 to work at the time, when the driver's side upper shock mount disintegrated. I wasn't even allowed to make a joke about uneven weight distribution.
Anyway I ended up removing both bump stops and fitting the chassis extension brackets. This was many years ago so at the time the Spax shockers were the preferred choice. I set them to the mid setting and have never had any bottoming out problems.
Last year I carried out a full rear suspension rebuild. My car has the rotoflex set-up. The Spax units were still in excellent condition so I refitted them. I did however replace all the transverse
spring rubber buttons which certainly improved things somewhat, even though the old ones looked OK.
I also discovered that one of the lower hub carrier bolt mounts had been sleeved with stainless steel. Resulting in the dreaded bolt virtually sliding out on disassembly- what a bonus! Has anyone else come across this mod before. Unfortunately the other side bolt was rather more resistant.
I ended up fitting grease nipples to both hub carriers so hopefully this will stop any future seizure of the bolts in their carriers.
Finally I discovered a trick to aligning the transverse spring bolt mount with the top of the hub carrier bolt mount-
Place a piece of hardwood between the top rotoflex coupling and the underside of the transverse leaf spring, before jacking up the hub carrier. I didn't have a spring lifter so used a combination of a trolley jack and large crowbar attached to the spring with two D shackles.
Jack up the leaf spring to the vertical position. Then jack up the hub carrier and the wood insert makes the hub carrier pivot at the rotoflex coupling and hey presto the two bolt mounts mounts line up.
Sorry if this went a bit off topic but I thought the last bit was worth sharing.

Cheers

Alan

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  • 1 month later...

Hi All,

 

Long time no see... Been a bit busy lately...

 

Gary - I can't confirm numbers now but I spoke to Garth ages ago and confirmed that my shocks match the Open and Closed lengths that he had written down.

 

Cookie - That's exactly what I did, got fed up with the stupid mounts ripping off and having to weld them back on, so when I did the rebuild I decided to ditch them... I never had a bottoming out problem before this though, the car sits higher with the new spring on now too, and it still does it more than I would see reasonable, granted it is now bearable and doesn't really bother me much. It bottoms out when I hit hard dips in the road at speed and when accelerating hard up steep and bumpy roads, otherwise it's okay.

 

Alan - I don't have any rubber buttons on my GT6's spring, I saw them on the diagrams on Canleys website etc... Not really sure where they go, doesn't look like they go anywhere in my particular spring, or the old one for that matter...

 

I haven't tried sticking a bump stop on yet to see if it makes it more comfortable yet...

 

Henry

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