John Morrison Posted February 5, 2020 Report Share Posted February 5, 2020 Fellow group Member has a serious leak which is coming from the adapter plate join, and I mean pretty serious. Pulled the box and split tonight and other than the gasket, can't see anything structural, like a crack, both faces do not seem warped. Anyone any thoughts before we just renew the gasket bolt together and re-fit. I'd be unchuffed if still leaked! John. Quote Link to post Share on other sites
foster461 Posted February 6, 2020 Report Share Posted February 6, 2020 John, when I had my TR3 gearbox and overdrive rebuilt the guy that did the work (very well known over here) swore that he had tested it by filling it with oil and letting it sit for a couple of days on the bench. Of course once I installed it and ran it the thing leaks like a sieve. He uses only the paper gaskets, no sealant. I dont know if that is the problem or if like other parts (draft tube, scroll seal) these cars were designed to leak. Stan Quote Link to post Share on other sites
John Morrison Posted February 6, 2020 Author Report Share Posted February 6, 2020 Understood Stan, but this box proves the old adage, if its not leaking, there is no oil in it! But this isn't a weep, it loses a pint a week! John. Quote Link to post Share on other sites
Chilliman Posted February 6, 2020 Report Share Posted February 6, 2020 If the nuts were done up properly & the adaptor plate wasn't warped then you're pretty much left with one choice - the gasket, & replacements like everything nowadays do vary in quality. The normal culprit for a leak of that scale near the centre is a warped adaptor plate - I rebuilt one last year that I found had been broken & 'glued' together & was also warped along the bottom edge. I got a new one from ORS which was a vast improvement on the original Stanpart - they have extended the double thickness machined surface all the way to the bottom which does away with the warping issue. Had mine bench tested on the jig for over an hour and all dry. Quote Link to post Share on other sites
John Morrison Posted February 6, 2020 Author Report Share Posted February 6, 2020 Thanks for that John, Certainly adapter plate isn't cracked, and I don't think its warped. Nuts were tight. Only thing I can see is some burrs on the bottom edge of the adapter plate, where a screwdriver or some such has beed used in the past to lever the plate and the overdrive apart, must have not helped sealing I think. You ever use a thin smear of Wellseal, when replacing this gasket, I know its really a 'No No' but we are where we are? john. Quote Link to post Share on other sites
Chilliman Posted February 6, 2020 Report Share Posted February 6, 2020 John, I've got no problem with using Wellseal on the gasket & have done so on the last few boxes. I won't use RTV or similar.... Quote Link to post Share on other sites
John Morrison Posted February 6, 2020 Author Report Share Posted February 6, 2020 Thanks John, Rex will be pleased! John. Quote Link to post Share on other sites
Chilliman Posted February 6, 2020 Report Share Posted February 6, 2020 How did I guess it was Rex...... Quote Link to post Share on other sites
Andrew Smith Posted February 6, 2020 Report Share Posted February 6, 2020 (edited) John, If the adaptor plate was a purchase in recent years (from Moss and whoever else they supplied) then there was a batch that were warped so it could be one of those? Pete Cox rebuilt a 4 synchro gearbox with OD for my 3A in 2017 and had to search long and hard to find a flat adpator plate. Cheers, Andrew Edited February 6, 2020 by Andrew Smith Quote Link to post Share on other sites
John Morrison Posted February 6, 2020 Author Report Share Posted February 6, 2020 Cheers Andrew, thinking I might recommend one of the re manufactured plates by ORS, as detailed above. Might mean I'm belt and braces on this job, even though it is easier with the now infamous gearbox crane! John. Quote Link to post Share on other sites
stillp Posted February 6, 2020 Report Share Posted February 6, 2020 Mine was just the gasket, the first time... then after I'd put it back together it was a warped adaptor plate! (Hamfisted reassembly). I then used a new Stanpart plate from TRGB, with Hylomar both sides of the gasket, and that joint is now one of the few places on the car that doesn't leak. Pete Quote Link to post Share on other sites
ntc Posted February 6, 2020 Report Share Posted February 6, 2020 Bet it is not flat new gasket and RTV both sides Quote Link to post Share on other sites
Hamish Posted February 6, 2020 Report Share Posted February 6, 2020 (edited) John I don’t want you to think I’m teaching you to suck eggs but you need to make sure the interior bolts are tight. and don’t over do the outside bolts I found my interior bolts loose and one fell out. the plate was good luckily And I use this sealant sparingly on both sides of the gasket. you can see that blue sealant was liberally used on my box and the od filter was full of it. I believe a contributory factor to the plate loosening was poor engine and gearbox mounts the torque effect I think was trying to twist the engine/ gearbox and the od join was the weakest area I replaced my engine and gearbox mounts with the revington up rated versions. all good now. Edited February 6, 2020 by Hamish Added mounting thoughts Quote Link to post Share on other sites
John Morrison Posted February 7, 2020 Author Report Share Posted February 7, 2020 Hamish, no worries, we are all always learning. Bolts are all tight, and there is no issue with the plate to gearbox, side of things, so we are definately looking at the plate to overdrive joint. Yours looked a mess! John. Quote Link to post Share on other sites
John Morrison Posted February 7, 2020 Author Report Share Posted February 7, 2020 Thanks to all who replied re this overdrive, Two more photos for you to comment on, one is damage on the internal raised 'Hoop' on the overdrive;- Second , this plate is flat, but there are these burrs, on the very bottom joint of the overdrive, looking like they were caused, by say a screwdriver to effect seperation sometime in the past. Very close to the site of the leak, and my thinking is that whilst sealing was effected for a long time, this slight 'Gap' encouraged the leak? Any thoughts? Because I think my plan would be to file the burrs , re-assemble with Hylomar and a new gasket, and see what happens. John. Quote Link to post Share on other sites
ntc Posted February 7, 2020 Report Share Posted February 7, 2020 As I said it will be bent on the edge due to bfh used to unstick the overdrive Quote Link to post Share on other sites
dingle Posted February 9, 2020 Report Share Posted February 9, 2020 I have had success in stopping this leak by using a rubberized gasket material (1/32" thickness) made by Victor Reinz and hylomar sealer. The permatex sealer became hard and brittle despite being labeled "non-hardening". Berry Quote Link to post Share on other sites
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