GT6 Rotoflex rear suspension

[Mike T]

Hi All

My winter project is to rebuild the rear suspension on a GT6 Mk 3 with rotoflex. This was partly to solve rear end clunks - turns out to have been drive shaft U/Js and some of the bushes are well worn.

 My issue has been that everything seems to be seized. I had to cut the bolt to get the both rear wishbones out from the chassis and the long bolt going through both the trunnions is seized solid. There appears to be no movement at all in the wishbone to rear upright joint. Is this normal? I assume I'm going to have to cut the bolt either side of the upright to separate it from the wishbone . Has anyone any tips on doing this and also thoughts on how to get the bolt out from the upright. I'm assuming that getting the bolt our of the wishbone should be easier.

Any suggestions gratefully received

Mike

[Clive]

That bolt is a nightmare. You are not the first....

Hacksaw will make short work of the bolt. And yes, the wishbone part is not an issue. But the upright can be very difficult. Usual things, heat hitting it (care not to damage anything) but sometimes drilling the bolt out is the only way. Not had to do it myself, but I have seen uprights where it has been done badly, ie not straight. Maybe a job for an engineering shop? 

But soaking in penetrating fluid for a few days, and keep trying the bolt with a big bar is worth a try. 

[trigolf]

I agree with Clive, the bolt is a potential nightmare. Many years ago I had the same problem and ended up taking it to garage who had to get a blowtorch on it and a v large hammer before it could be 'persuaded' out. To reduce the problem I bought stainless steel trunnion spacers from Canley Classics and reassembled with plenty of Copaslip. Every year I put up the car on stands, slacken the trunnion bolt nut and give the bolt a turn to make sure, then re-tighten to the correct torque, to prevent it seizing.

[Guest]

Hello Mike,

I had some similar issues when I was converting my Mk2 Vitesse to a CV set-up.

Really struggled with one side of the car but from there with experience and as Clive has mentioned I spent a few days soaking all the bits that needed to be removed with Plus Gas; whereas initially I was only allowing about twenty minutes for the penetration to work. Do not use WD40 as it is not a rust breaker but a water repellent and as such you will be wasting every minute of your time & effort.

It is important to remember that it is the bolt you need to shift rather than the nut which can be retained in situ to assist with the unlocking action of the bolt. By that I mean it is worth ensuring the nut does not move and all the force is placed upon the bolt head - certainly worked for me on occasions.

Secondly, the use of a serious long breaker bar is a must as it is the initial "shocking action" that frees the bolt. You have nothing to lose, because if it shears it is a machine shop job and if it does not budge it's still a machine shop job.

When I had my hubs machined for the NJ conversion, one of the long bolts would not shift and nor could the machine shop budge it and they work on marine size issues !! The bolt had to be drilled out and if you are faced with that, then I would suggest it is worth the machine shop doing the job as they will be geared up for such tasks.

As with all difficult bolt uncoupling, it is also worth trying to tighten the bolt - I know, sounds odd but it does work in some cases and can be just enough to break the hold; as can the back and forth action upon the bolt head.

It goes without saying that all sockets and ring spanners need to be A1 sharp without any play on the sides or you will introduce another problem in to the "Game of Bolts".

Again, as mentioned, heat applied is very useful and plays its part

On reassembly I used plenty of Copperease where appropriate which was pretty much most areas; which should hopefully assist a future strip down if ever required.

As for bush replacement I went poly including the diff, of which I know you have a separate thread running.

Finally, before signing off, I have just started to experiment with ATF mixed with Acetone which via other classic vehicle enthusiasts comments, appears to have the same if not better breaking properties than Plus Gas - the jury is still out at the moment. 

Good luck.

Regards.

Richard. 

[Nick Jones]

Pretty comprehensively covered above.....  I have done many of these.  A few come straight out, others take literally days.  I've also seen the aftermath of many a botched drilling out attempt.  It really needs to be done in a mill,

Don't cut the bolt until all other avenues are exhausted.  Proper penetrating oil, serious heat (repeatedly sometimes), and strong bench/vice and a long breaker bar are your allies.  I have even been known to drill small holes through the wall of the link into the bolt to allow the penetrating oil a better chance of getting in there.  These need to be welded up (or similar) afterwards although I know some like to put grease nipples into them.

As for the radius arm bracket bolt - unless you have a really pressing reason, just leave it be!

Nick

[Mike T]

Thanks for all the comments. As suggested I'll try to move things with the bolt in place to start with and only cut the bolts if that fails. The radius arm bracket bolt will definitely be left alone!

Mike

[Adrian]

When I did mine I cut the wishbone bolt and had it professionally drilled out and on reassembly, lots of copper slip and extra washer to take up the play from the slight loss during cutting. One of the radius arms was seized solid in the link...so I left it alone. Makes reassembly a little awkward but not insurmountable.

When stripping down the bush in the leaf spring was almost non existent, all the rebuild used blue superflex.

Adrian

[Mike T]

A quick update - I ended up cutting the bolt and both uprights are away having the remains of the  bolts drilled out.

As part of the stripdown of the rear suspension I am replacing the U/Js in the drive shafts as one had a lot of play. When I got this U/J out there were no rollers there and the edges of the caps were breaking up. Any idea what might have happened to the rollers and is this usual?

Mike

[Clive]

You had a lucky find there, left alone that would have been nasty.

How it happens? I know somebody who had a set of rotoflex rebuilt by a (now defunct, thankfully) trader. He fitted them, and a few years later the car got on the road. After a few hundred miles, he checked everything over, and discoverd play in both UJs.

Stripped, etc, grease but no rollers in there, no signs of escape. Conclusion was that the numpty had assembled them without the rollers. Dreadful, and the trader didn't want to know. Chap didn't keep quiet about it, but then no internet so only word of mouth.

Anyway, that is one possibility. Not sure but I don't think rollers can escape easily, especially if the rubber seal is still fitted. If that has gone, I suppose they will break up and fall out?

But makes no odds, you can fit decent UJ's correctly and all will be well.

[Mike T]

I am now onto the re-assembly stage. I have purchased the PU bush kit for the rear suspension rebuild from the club shop, the kit does not come with the inner/outer water shields and O rings that fit on the trunion bushes. Do the polyurethane bushes not need them? If they do I'll have to purchase a set as they were destroyed in the removal process.

 

Mike

[Guest]

Mike,

When I fitted PU to my rear trunnions, I used the rubber O ring and end cups.

I just assumed that it was necessary to do so as the caps help to prevent ingress of dirt causing corrosion to the long bolt and general wear.

As such I cannot give you a definitive answer, just indicating what I have done.

Regards.

Richard. 

[GT6M]

it is a great move t,drill the VL  an tap it 5/16,

 2 a side, just next t,the VLs legs, going onto the bolt carrier,

also same on top of each lower arm bushing,

on thee,s it needs t,go thru the inner bush,

 

then just fit a blank plug t,the outer,ns, ora grease nipple.

 

the VL is diff, as bolts need t,grip the lang bolt, so it dont move

this cos most oft VLs, the hole is worn at ends,, this stops the play.

Also, every noo an then, tek bolts oot an oil, turn bolt t,get oil thru the VL

 

Niva ed a rusted in bolt in mine all thee,s years

 

this ont olde set up.

 

seal,n an note wee wol in inner end

 

modded bolts an bush  fer oil flow

 

nipples on bushes

 

meb,e some use t,ye, t,stop yer bolts an bushes rust,n in situ

 

M

 

 

 

[Guest]

On ‎16‎/‎03‎/‎2019 at 21:21, Mike T said:

I have purchased the PU bush kit for the rear suspension rebuild from the club shop, the kit does not come with the inner/outer water shields and O rings that fit on the trunion bushes. Do the polyurethane bushes not need them? If they do I'll have to purchase a set as they were destroyed in the removal process.

Marcus,

Nice upgrade and thanks for posting.

Mike was actually asking the Q in the quote box above - perhaps you can give a yes or no answer to that ??

Or to that end, can anyone provide a definitive answer ??

Regards.

Richard.

[johny]

This has come up before and the result was that as the bushes are now stainless steel they wont corrode so dont need sealing..... 

[Guest]

Thanks johny.

Regards.

Richard.

[GT6M]

 Rich, They need sealing, or oiling, oiling on a regular basis,

IF the car is used alot, esp int wet / damp. if not got decent seals in spot.

 

reason, the bushes meb,e stainless, { wrong grade in my mind for us lot woe live ont coast }

but the bolts aint, so they get a coating of something on em, an then stik fast. believe me, they stik, even moer so than an OE bush,

dissimilar metals ye no,!!

 

even some nylon weshers, wid oot the O rings like on mine will seal better than the useless metal things

they just dont stop moisture seep,n doon the ends, and into the VL an  wishbone holes /bushes an bolts.

the nylon weshers can be med a tight fit between VL an wishbone, tap em in wid a wee hammer,

then whenst bolts tightend up, it will draw the ends oft wishbone in a bit further, so mek,n a total seal

 

whilst its off, it just teks a short time t,dee what I did, and all problemos are solved

 

even got em on me shocker mounts , infact there every where,!!!

nowt moer  grrrrrrr-able than coming t,do a 10 min job, an yer at it 3 days !!

 

M

[Mike T]

Hi all

Now into reassembly mode but looking for a bit more assistance. I pre-assembled the drive shafts/hubs and am trying to mount into the car. The drive shaft is attached to the diff, rotoflex's fully bolted up and lower wishbone fitted. This leaves just the top of the upright to bolt to the spring but I can't get them to line up. I still have the steel band around the rotoflex and am thinking if I remove this it will allow more movement in the upright so I can line up with the spring. Am I right in this thinking or should I have assembled in a different order.

Any tips?

Many thanks

Mike

[dave.vitesse]

Mike, The standard method is to use a spring lifter to help align the spring with the upright. Even then it can be difficult and a spike/dibber can be used to pull one side of the upright in line with the spring. This has to be held in position whilst the bolt is pushed into the other side.

The problem you have is the normal pain when re-assembling Rotoflex.

Dave 

[Paul H]

I found using the spring lifter at max lift then using a scissor jack under the hub you can “nearly “ get the alignment you need then it’s a case of carefully drifting in the top bolt to get alignment, using a screwdriver to assist. This worked on one side but found the other impossible so purchased a longer bolt and ground a point to aid the alignment. Once through I bolted every thing down and cut off the point . The purist would put in the pointed bolt in the wrong way and then drift in the bolt pushing out the pointed bolt . This is one of the hardest jobs to do on the Vitesse according to Canleys 

Paul 

[Mike T]

Thanks for the replies. Does it make a difference removing band round the rotoflex or is better to this once everything is back together

Mike

[Paul H]

Personally I didn’t think it made any difference , others might disagree 

Paul 

[Qu1ckn1ck]

We had some difficulty doing the same job last Friday, but got there in the end:

[Mike T]

Any tips on how you did it. I can't get the upright close enough to the spring to even try the ground down bolt suggestion.

Thanks

Mike

[daverclasper]

On 30/01/2019 at 14:32, Nick Jones said:

As for the radius arm bracket bolt - unless you have a really pressing reason, just leave it be!

Hi Nick. Is that the bracket to outrigger fixing, or the bush fixing please.

Cheers, Dave

[dave.vitesse]

If you haven't coupled up the U/J's yet then leave the band on until you do.

I agree with Paul in using a jack under the upright it does help.

Dave