johny Posted April 6, 2023 Report Share Posted April 6, 2023 9 hours ago, thescrapman said: Did you fit a brand new synchro cone, or a good secondhand one? Scrapman do you have any idea of the symptoms you get it the 1/2 gear synchro inner hub is installed the wrong way round? Reading through old threads on the subject I see one poster had problems selecting 3/4 and the mainshaft had a longitudinal crack in it! Link to comment Share on other sites More sharing options...
Josef Posted April 6, 2023 Report Share Posted April 6, 2023 18 minutes ago, johny said: Scrapman do you have any idea of the symptoms you get it the 1/2 gear synchro inner hub is installed the wrong way round? Reading through old threads on the subject I see one poster had problems selecting 3/4 and the mainshaft had a longitudinal crack in it! Pretty sure in this case Johny that’d be extremely obvious. This is a three synchro box right? So the inner of the 1/2 hub is a few inches long and only has space for a synchro ring on one side. Link to comment Share on other sites More sharing options...
johny Posted April 6, 2023 Report Share Posted April 6, 2023 Of course, I was thinking 4 synchro... 1 Link to comment Share on other sites More sharing options...
KevinR Posted April 6, 2023 Report Share Posted April 6, 2023 7 hours ago, Jonah said: I fitted new ones from Canley as part of a rebuild kit Julian That might be part of the problem. I’m sure Pete will elaborate the reason, but it boils down to the machining process for the new ones that makes them slightly misshapen. Good old ones are far preferable to new ones. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 7, 2023 Report Share Posted April 7, 2023 you need to wring the ring onto the cone to make sure it grips ( a good push and twist action) problem baulkrings were machined in a lathe chuck so the grip of the jaws deformed the ring they must be machined on a mandrill or you get lobed useless rings these will rock on the gear cone not fully grip it but none of that should block engaging 2nd gear when stationary Dave at Canley knows what he's at i would expect their rings to be OK 1 Link to comment Share on other sites More sharing options...
Jonah Posted April 8, 2023 Author Report Share Posted April 8, 2023 When I disassembled the gearbox the 3rd and 4th rings seemed fine, 2nd had no grip at all and was really loose i replaced all the rings with the new Canley ones so still have two from the previous build the box is on the bench and I’m in the process of getting the main shaft out getting it out of the car the second time was so much easier with the benefit of experience! julian Link to comment Share on other sites More sharing options...
johny Posted April 8, 2023 Report Share Posted April 8, 2023 The thing is its difficult to think of anything that would prevent the hub outer sleeve from engaging with the main gear. The synchro ring would have to be awfully out of round to keep the hub so far away that this was the result! Link to comment Share on other sites More sharing options...
Jonah Posted April 8, 2023 Author Report Share Posted April 8, 2023 I’m itching to get the mainshaft out and I’ll post some photos she who must be obeyed has banned me from the garage todayin favour of a garden centre!! Link to comment Share on other sites More sharing options...
johny Posted April 8, 2023 Report Share Posted April 8, 2023 Id do it nice and slowly, testing the hub operation frequently so as not to dismantle it without finding the cause! Nothing worse than having a pile of bits with no obvious problem😰 Link to comment Share on other sites More sharing options...
Jonah Posted April 9, 2023 Author Report Share Posted April 9, 2023 I disassembled the mainshaft carefully but couldn’t see any obvious mistakes in the assembly looking at the synchro hubs the rings are a good tight moving fit i disassembled the hubs to remove the springs and ball bearings, the longer springs were fitted to the 3rd/4th hub, is that correct? I couldn’t find any shims under any of the springs which may be correct the only other thought I had was whether the 1st/2nd hub plunger under the ball bearing was aligned properly as the sleeve was inserted julian Link to comment Share on other sites More sharing options...
johny Posted April 9, 2023 Report Share Posted April 9, 2023 Yes I think the shims are probably only needed as the springs weaken with age and then best to replace them. Cant remember with spring length but think the WSM shows correct set up... Link to comment Share on other sites More sharing options...
Jonah Posted April 9, 2023 Author Report Share Posted April 9, 2023 Thanks Johny, the WSM doesn’t seem to indicate which hub should have the longer springs, but they’re definitely different lengths between hubs i can see from the WSM how I might have missed aligning the master spline with the interlock plunger correctly Link to comment Share on other sites More sharing options...
johny Posted April 9, 2023 Report Share Posted April 9, 2023 Looking at the sectional diagram of the gearbox the spring pockets of the 3/4 hub look deeper than the 1/2 so should have the longer springs. Perhaps you can confirm this by measuring their relative depths? This is also backed up by looking at the springs for sale at Rimmerbros whose diagram also shows a spacer at the bottom of each pocket but of course its pretty difficult to verify if you got one in there or not... Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 9, 2023 Report Share Posted April 9, 2023 long springs for 1/2nd shorter are 3/4th the shims are to adjust the "pop" load of the sleeve and not normally needed if you have some bathroom scales its easy enough to click the sleeve and watch for the load reading i wouldnt bother it moves quite firmly by hand it will work ok in the box did you try operating the sleeve with the mainshaft out before disassembling it ??? Pete Link to comment Share on other sites More sharing options...
johny Posted April 9, 2023 Report Share Posted April 9, 2023 Are you sure about the springs Pete as it seems counter intuitive and certainly doesnt tie up with the photos on Rimmers... Link to comment Share on other sites More sharing options...
johny Posted April 9, 2023 Report Share Posted April 9, 2023 Looks like the more expensive spring goes on 1/2 but apart from length is one slightly beefier than the other? Link to comment Share on other sites More sharing options...
johny Posted April 9, 2023 Report Share Posted April 9, 2023 Just checked a box Ive got in bits and the 3/4 hub has springs with length 13/32" but couldnt get the 1/2 ones out to compare... Link to comment Share on other sites More sharing options...
Jonah Posted April 9, 2023 Author Report Share Posted April 9, 2023 I’ll measure them Johny, you’re right one set looks beefier than the other julian Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 9, 2023 Report Share Posted April 9, 2023 the long and short is how i remember it but thats not to say the grey matter has it mixed what you do need is the sleeve detent break load to be something like whats in the manual i ask again did you try to shift the sleeve with the mainshaft on the bench ??? as said simple test is bathroom or similar scales and fire the sleeve off its detent watch the load you get if its too high fit the shorter springs and recheck wehave done all this a longtime ago but i cant find it 1 Link to comment Share on other sites More sharing options...
Jonah Posted April 9, 2023 Author Report Share Posted April 9, 2023 Thank you Pete, unfortunately I didn’t have the foresight to try shifting the sleeve with the mainshaft on the bench ,it exploded as I removed the shaft i’ll take the measurements now Link to comment Share on other sites More sharing options...
Jonah Posted April 10, 2023 Author Report Share Posted April 10, 2023 Both hubs are reassembled and the break loads both measure 20lbs I’m very confident that I hadn’t aligned the second speed synchro unit with the master spline when I originally assembled the mainshaft, so hoping this was the cause of the problem on inspection I’ve noticed damage to one of the 3rd speed mainshaft gear teeth, pic below, was wondering if this is significant enough to need a replacement? thanks Julian Link to comment Share on other sites More sharing options...
johny Posted April 10, 2023 Report Share Posted April 10, 2023 I think best to accept that damage as its minimal and any new gear wont be worn to the laygear so could generate worse noise. I take it the synchro hub in the picture isnt pushed fully home as its not completely engaged with the gear is it? Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 10, 2023 Report Share Posted April 10, 2023 (edited) if its the small chamfered loss on the end of the tooth just use a carborundum stone to fettle a lead in to the tooth chip on production small tooth marks were ground off before the days of dremmels if the gear produced a knock so they just removed /smoothed the offender with a whizzy grinder its not in a full contact zone , not to worry if you had the 2nd gear hub lock out of align that would stop the sleeve and baulkring aligning so think you have the culprit Pete Edited April 10, 2023 by Pete Lewis Link to comment Share on other sites More sharing options...
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