trigolf Posted February 21 Report Share Posted February 21 Don't forget that the trunnion bolt is torqued up to 55-60lbs ft, so the rubber seals will compress a bit over time. I would be wary of grinding any metal off. Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 22 Report Share Posted February 22 i would expect the crush tube should protect seal crushing ?? Pete Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 22 Report Share Posted February 22 as the main components all measure to spec it would seem the seal cups are too thick there is little else to upset the fit ?? spreading the wishbone is an option but not a liked solution Pete Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 22 Report Share Posted February 22 (edited) I would be very wary of trying to spread the wishbone, I believe they are cast and you are likely to break something. I would do as Trigolf suggest and put the vertical link in a vice and then try and fit the assembly using a soft faced hammer (Nylon/Copper) to hammer the wishbone over the vertical link. Another option is to use a couple of 'G' Cramps to compress the bushes whilst trying to fit the wishbone onto the vertical link. If all this fails, then maybe carefully grinding or machining 1mm off each side of the vertical link may be the only option. Gary Edited February 22 by Gary Flinn Link to comment Share on other sites More sharing options...
trigolf Posted February 22 Report Share Posted February 22 As Peter T says even when all parts are def. correct spec, assembling the wishbone to the v link is very tight, not helped by the dirt shields tilting as they are 'persuaded' onto the v link. Another pair of hands helps, but if all else fails - how about putting a nylon tyrap through both wishbone legs to hold the shields in place until you at least manage to get them started and wedged in a bit. Then cut the tyraps off before tapping into place to line the bolt holes up? Just an idea... 1 Link to comment Share on other sites More sharing options...
johny Posted February 22 Report Share Posted February 22 1 hour ago, Pete Lewis said: i would expect the crush tube should protect seal crushing ?? Pete Thats an interesting point as I wonder how the crush tube length compares with the assembled trunnion? If its not slightly longer then its a clear indication something is wrong in the bushes/seals/plates because they will get clamped and mashed by the movement of the upright and wishbone... Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 20 hours ago, Gary Flinn said: Pete I've read in the past that two types of Vertical link castings where supplied for rotoflex cars, could one be slightly wider for some reason? Have a read of this link and back in the room again! There are two types of link. Peter has the wider ones which look like they have cast on washers. Whereas the other type is plain cast at the bottom, and needs selective washers to make up the considerable gap. 1 Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 22 Report Share Posted February 22 Surely the principle of these rear trunnions is as per the front ones, the steel tube should be clamped tightly so it's correct length is critical, then the Nylon trunnion bushes pivot on the tube, isn't that the principle? I've stripped these down before and found the hole in vertical link way oversize because the rear suspension vertical links been pivoting on the bolt due to the steel tubes being rusted solid onto the long bolt! I can remember reading years ago a technical write up in the Courier on the lower wishbone suspension by someone called Eickhoff, he goes into great detail on the ideal position for the inner wishbone lower pivot point and I'm sure he had a go at fitting sealed bearings in place of the trunnion bushes too. All in all this rear trunnion bush arrangement isn't ideal and is very prone to seizing up. Gary Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 18 hours ago, Puglet1 said: Hi Gary. Thank you for the link. After reading it, I can confirm that the ones fitted to my car are the same dimensions as given in the workshop manual therefore should require the standard washers / dust cover and NOT the thicker ones that Htiek required. This makes me wonder if I have the “Thicker (TR7?) type washers/ dustcover and rubber seals. I’m hoping David from Canley classics can help? "Thicker TR7 type washers/dustcovers, etc" I wasn't aware such a thing existed, where do they fit on a TR7? Our roto kits are for roto GT6, and Vitesse. Link to comment Share on other sites More sharing options...
johny Posted February 22 Report Share Posted February 22 16 minutes ago, Gary Flinn said: I've stripped these down before and found the hole in vertical link way oversize because the rear suspension vertical links been pivoting on the bolt due to the steel tubes being rusted solid onto the long bolt! Gary The steel tubes always rust on to the bolt but I cant see this being a problem (until strip down) as the bushes can still rotate freely on the tubes... 1 Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 Co-incidentally I had Mick Papworth (he was here borrowing our o/d test rigs, and the lathe) sat opposite me yesterday in the office, and we were discussing this because he had noticed the roto bush bits on the desk with my vernier from earlier. He had a careful look at them, its nice to have a second pair of eyes, I thought I was going mad! Anyway Peter has just been on the telephone, and I have offered him a refund which he seemed happy with. Good luck Peter, I hope you find a solution to your problem. David Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 30 minutes ago, Gary Flinn said: I can remember reading years ago a technical write up in the Courier on the lower wishbone suspension by someone called Eickhoff, he goes into great detail on the ideal position for the inner wishbone lower pivot point and I'm sure he had a go at fitting sealed bearings in place of the trunnion bushes too. All in all this rear trunnion bush arrangement isn't ideal and is very prone to seizing up. Gary He initially recommended Metalastic bushes to replace the plastic trunnion bushes. I drove a Vitesse that had been fitted with those as per that advice. I nearly drove into the ditch at the first corner I came to! Change of underpants time! I hope that he did change that advice later to something like sealed needle rollers. or the like. 1 Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 22 Report Share Posted February 22 5 minutes ago, Works Spitfires said: He initially recommended Metalastic bushes to replace the plastic trunnion bushes. I drove a Vitesse that had been fitted with those as per that advice. I nearly drove into the ditch at the first corner I came to! Change of underpants time! I hope that he did change that advice later to something like sealed needle rollers. or the like. I believe people have fitted Polybushes too in place of the Trunnions, I wonder if they give interesting handling too? Gary Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 Just now, Gary Flinn said: I believe people have fitted Polybushes too in place of the Trunnions, I wonder if they give interesting handling too? Gary Never understood the extra expense of Polybushs here. The specification of the original plastic bushes (and our locally made repros) was never an issue. Has anyone ever seen an badly worn roto plastic bush? 99% of the ones I've removed which have generally been 50 +year old originals come out looking like they would go again (after cleaning off the rust from the wishbone/steel spacers). 2 Link to comment Share on other sites More sharing options...
Works Spitfires Posted February 22 Report Share Posted February 22 Anyway, back to the workshop, I have some close ratio 'works' Spitfire gearboxes to build. 1 Link to comment Share on other sites More sharing options...
Puglet1 Posted February 22 Author Report Share Posted February 22 I have spoken to Mike Papworth and have also managed to locate some NOS water shields and seals. Mike has told me that Canley parts are amongst the best available so I have decided to try fitment with the NOS parts. Next opportunity to get in the garage will be sometime next week. Watch this space. 1 Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 22 Report Share Posted February 22 1 hour ago, Puglet1 said: I have spoken to Mike Papworth and have also managed to locate some NOS water shields and seals. Mike has told me that Canley parts are amongst the best available so I have decided to try fitment with the NOS parts. Next opportunity to get in the garage will be sometime next week. Watch this space. Good luck with it and keep us all posted how you get on?🙂 1 Link to comment Share on other sites More sharing options...
johny Posted February 22 Report Share Posted February 22 3 hours ago, Works Spitfires said: Never understood the extra expense of Polybushs here. The specification of the original plastic bushes (and our locally made repros) was never an issue. Has anyone ever seen an badly worn roto plastic bush? 99% of the ones I've removed which have generally been 50 +year old originals come out looking like they would go again (after cleaning off the rust from the wishbone/steel spacers). I thought one of the great things with polybush was the stainless steel sleeve that avoided the problem of them rusting onto the bolt and having to be cut out. I would certainly be interested in any of the trunnion kits that has the original plastic bushes but with stainless sleeves so getting this benefit without the expense of silicone👍 Also David whats the way forward with the rotaflex bush kit now then? I think perhaps some measurements could be taken and a recommendation made that theyre not suitable for any car with less than a certain clearance between the wishbone and upright... Link to comment Share on other sites More sharing options...
KevinR Posted February 22 Report Share Posted February 22 3 hours ago, johny said: I thought one of the great things with polybush was the stainless steel sleeve that avoided the problem of them rusting onto the bolt and having to be cut out. I would certainly be interested in any of the trunnion kits that has the original plastic bushes but with stainless sleeves so getting this benefit without the expense of silicone👍 Using stainless steel sleeves will not stop the corrosion, it will just change the source of the corrosion, and may make it worse. The only guaranteed way to stop the corrosion is to also use stainless steel bolts - and that is a VERY BAD idea and should not be done. The problem of dissimilar metals is Galvanic corrosion. The further apart the metals are on the the scale, the worse the corrosion. To minimise galvanic corrosion, you really need to keep the potential difference less than 0.1V Using a good high quality highly water repellent grease, such as Molykote Longterm W2 in the sleeve will help minimise corrosion. Under no circumstances should one use copper grease. Link to comment Share on other sites More sharing options...
johny Posted February 22 Report Share Posted February 22 wow Kevin so you think Polybush and others would do better to use non stainless steel sleeves? Link to comment Share on other sites More sharing options...
Peter Truman Posted February 22 Report Share Posted February 22 Kevin Interesting comment re copper grease, like most other classic car nuts I've used it for years to stop bolt thread & bush seizure it seems to work the grease does go black and gets thick but the parts do come undone! The Galvanic table & statement that to avoid corrosion the potential difference less than 0.1v is food for thought esp when you see where mild steel is relative to other metals s/s and brass, copper etc it doesn't give us much chance? your comment re Molycote Longterm grease is noted & I'll get some. For our large steel water mains a heat applied thick sprayed on (8mm ) epoxy coating with impressed current and sacrificial anodes is the answer then we affect other authorities assets and it becomes a horse trading which asset is to be sacrificed exercise. Link to comment Share on other sites More sharing options...
johny Posted February 22 Report Share Posted February 22 I can confirm that copper grease isnt conductive as far as a multimeter goes anyway... Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 28 Report Share Posted February 28 (edited) On 22/02/2024 at 12:38, Puglet1 said: I have spoken to Mike Papworth and have also managed to locate some NOS water shields and seals. Mike has told me that Canley parts are amongst the best available so I have decided to try fitment with the NOS parts. Next opportunity to get in the garage will be sometime next week. Watch this space. Any Progress yet with the Suspension rebuild? Regards Gary Edited February 28 by Gary Flinn Link to comment Share on other sites More sharing options...
Puglet1 Posted February 28 Author Report Share Posted February 28 8 hours ago, Gary Flinn said: Any Progress yet with the Suspension rebuild? Regards Gary Hi Gary. The rear lower wishbone to vertical link is assembled for each side of the car. This was achieved by Using the Canley supplied plastic bushes (which were to original spec) along with New Old Stock washers and rubber seals which I managed to source from another supplier. The vertical link slid into the lower wishbone using heavy hand pressure only. I measured the thickness of the Canley supplied washers and found the material to be 0.82mm compared to 0.40mm of the NOS ones. The lips on the large holed Canley washer measured 2.93mm compared with 2.09mm NOS. The rubber seals were of similar dimensions for each supplier. The small holed washer material thickness also reflected the large hole washers from each supplier. The additional 0.42mm of the Canley washers alone multiplied by 4 equates to 1.68mm additional interference when being assembled to the wishbone. I believe almost 2mm interference of these parts prevented me from assembling the wishbone to vertical link . I have attached a couple of photos below as David originally stated that it would be good to help others understand this concern. Thickness of NOS washer. Thickness of Canley supplied washer Lip on NOS washer. Lip on Canley washer. As a word of advice for anyone considering trunnion bushes I’d suggest you keep your old washers if possible. I hope this helps. Pete. 1 Link to comment Share on other sites More sharing options...
Gary Flinn Posted February 29 Report Share Posted February 29 Glad you've managed to sort it🙂 It's just a matter of refitting it all to the car now then? Gary Link to comment Share on other sites More sharing options...
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