Michael Southgate1 December 2018 at 05:38 #52942
Hello Lagonda Land,
As I pulled into a petrol station the other day and went to grab for a lower gear, it seems the clutch on the LG6 stopped working.a I could only get first or reverse by stopping the engine, selecting the gear, then restarting. Only with the clutch pedal right to the floor was I able to start “out of gear” and the clutch took up in about 5 mm. The clutch was a little stiff/notchy earlier in the journey but it’s done that before and come good.
I believe I’ll need to take the clutch out, but before I do this, does anyone have any suggestions regarding what this might be and whether a fix might not involve removing the clutch? If the clutch does have to come out, any advice, tricks or tips on how to do this? I’ve been having a look and it doesn’t seem easy. I have the seats and floorboards out, but if the shaft between engine and gearbox needs to come out, I don’t see how that can happen without also removing the gear shift mechanism which sits over it.
Ideas and advice gratefully received, also posted on the Facebook forum in a more brief form.
Many thanks in advance, Mikeh141 December 2018 at 10:38 #52944
Sorry to hear of your trouble; breaking the starter armature must have resulted in some choice language! Assuming you didn’t use extreme force removing it however, it must have been near the point of failure anyway, so as well it occurred in your garage.
Regarding the clutch, the symptoms you describe can sometimes be resolved by adjusting the clutch pedal setting to the factory specification. So check that and adjust first. If the problem is still evident, get someone to operate the clutch pedal up and down, whilst you check each part of the linkage for inappropriate movement or seizure.
To remove the cardan shaft, you will need to remove the gearbox mounting bolts and move it backwards. No more than an inch; just enough to enable the safety spike on the cardan shaft to disengage it. ESSENTIAL: mark the cardan shaft flexible couplings and spiders for identical reassembly, and ensure all the bolts, washers and nuts attaching them are returned to their original positions. Failure to do this could well result in unwanted driveline vibration.
The gear lever tower is no problem at all. The casting is held down by four bolts; remove those, and the entire assembly lifts away. There are locating dowels, so re-engagement is easy. Do not loosen, remove or adjust the operating fingers.
Let me know if more advice needed. Perhaps I can take this opportunity to state that I’d still like to know the body number of your drophead! Email me if you prefer; the number will be a four digit number commencing 75.
LaurenceMichael Southgate2 December 2018 at 07:52 #52948
Thank you Laurence for your reply.
No choice words on finding the starter motor pinion on the floor, just surprise… ;). I hadn’t planned on removing it until it happened, so it wasn’t my hamfistedness that caused it (this time…).
Thanks for your advice on removing the cardan shaft. I was hoping not to move the gearbox to avoid the risk of misalignment – I read another thread describing how to re-align and I don’t really want to go through that. Also, wouldn’t that involve disconnecting the prop shaft off the rear of the gearbox? Can you gain that inch just by removing the flexible couplings, or is there something that goes through their centre that means you can’t slide them out after all the bolts are removed?
Thanks for the description of the removal of the gear selector, I feel more at ease about that now. I’ll also have to re-consult the manual I have for adjusting the clutch before I take the drastic measure of removing the assembly.
Finally, where is the body number located? All I’ve found is a brass plate on the firewall which is stamped with the type (LG6.DHC), and the engine and chassis number I think (both of which are 12310). The engine is stamped with LG6/444/S4 and 12310. There are two other plaques in the door openings just above the running boards on either side which say “coachwork by Lagonda” but no numbers. Is there anywhere else I should look?
Many thanks again,
Mikeh142 December 2018 at 12:47 #52950
No need to remove the gearbox, you just need to move it back a little, perhaps just half an inch. The propshaft telescopes, so no need to work on that. The forward end of the gearbox is mounted on rubber bushes in aluminium castings via a through bolt. Don’t unbolt that, remove the bolts holding those castings to the chassis. You will probably find there are red fibre shims between these castings and the chassis … ensure those don’t get damaged and that they are noted for original positioning. The left hand aluminium casting is inadequate in service, and often found to be broken.
The rear gearbox mounts are simply a vertical bolt each side; look out for washers serving as shims and note for original positioning. These front and rear mounting bolts enter accurately drilled holes in the chassis, so provided you ensure all shims as mentioned are replaced in their original positions, alignment should be precisely retained. The cardan shaft has a spike at each end; the purpose of this is that, if the flexible coupling shears, the shaft will not flail dramatically, but be retained within the spider. The downside of this safety arrangement is that the spike will not disengage until the gearbox is moved rearwards. It follows that you only need to move the gearbox enough to disengage that spike.
So unbolt the flexible couplings first. The gearbox is (naturally!) extremely heavy, and a trolley jack would be ideal for moving it, but if you’re strong enough you should be able to move it by hand. I’ve attached a reduced photo of the spike in situ, but I’ll email it to you separately, with others that may help. As my LG6 is a special, the entire gearbox etc is easily rendered visible!
At least, if it proves necessary, you should have reasonable access for removing the clutch cover and driven plate, no bell housing being in the way.
The firewall plaque always states the engine number as the chassis number[ the true engine number is, as you’ve found, stamped on the engine. The body number is stamped, scratched or pencilled on pretty well every body component. If you’ve removed the seats, if like my V12, you’ll find it pencilled on the metal runners screwed to the base of the seat, so should be visible simply by turning a seat upside down. The easiest place to find it should be on the inner face of the actual (ie right hand side) spare wheel cover, between the catches. If like my V12, you should also find it scratched into the underside of the little chrome trim plates attached to the end of the hood frame members. If no joy, let me know and I’ll investigate other locations.
LaurenceMichael Southgate5 March 2019 at 22:27 #52991
Well, the clutch was removed and taken to a local specialist, and they’ve finally confirmed that they can rebuild the pressure plate. It should be done by the end of this week, and the cost wasn’t too unreasonable.
I will also have the carrier bearing replaced, which should also be no problem.
This just leaves the thrust bearing, which I got apart to remove the bearing. It’s branded FBC and marked XLS 1-7/8 and should be commercially available. The question is, is it the correct bearing? The one available through the club spares looks different.h146 March 2019 at 11:07 #52992
Clutch thrust bearings on cars of this era were usually a pressed in graphite ring. Your car may have been modified to take this bearing, furthermore if original, I’d expect to see it was made by R & M, ie Ransome & Marles. The advantage of the graphite ring is that it is of course self-lubricating.
LaurenceMichael Southgate6 March 2019 at 12:12 #52993
As usual, very helpful with information. For a thrust bearing, I’d have expected the races front and back, rather than inner and outer as this one is. Any idea where an original type can be found? I’ll take some measurements of what was in it to find a suitably sized thrust bearing replacement.
Mikeh147 March 2019 at 10:10 #52994
You’re welcome. Unfortunately I’ve never dismantled an LG6 / V12 clutch assembly, so can’t be definitive. I can say that many years ago, at an autojumble at Biggin Hill, I was astounded to discover a new old stock Borg & Beck clutch plate for LG6 and V12. I gave this to the guy who rebuilt my V12’s mechanics, only to get it back as he’d forgotten it and fitted a new one. He also returned the original, which was worn down just to the rivets, despite which I don’t recall it slipping.
I’m assuming we’re talking about the same part? By thrust bearing I’m assuming you intend what I’d refer to as the clutch release bearing, the component which bears against the sprung facing of the cover plate to withdraw the drive plate, thus freeing the clutch plate.
So new driven plates are out there. This one carries the B & B part number 40249, and I guess dates to the early 1950s as the leaflet inside lists clutch parts for cars of that era. If it helps, the box states 11″ facings, and that it also fits … Commer Q2,Q3, Q4 Diesel 1939/49, Humber Snipe 1938, Guy Otter 4-5 Ton 1936/45, Karrier CK3 674 Series 1947/52. Whether thathat might help in sourcing other clutch components, I don’t know.
I have the floors etc out of the V12 so I’ll have a look at that later. I do have clutch parts for my 1951 Riley RMB available to photograph, which may be similar.
Laurenceh1410 March 2019 at 21:52 #52996
Managed to get over to look at the V12 today. I can see the clutch operating linkage, but can only say what I can see has no similarity to the the release bearing on my Riley. Perhaps someone who has dismantled a V12 or LG6 clutch assembly will advise.
LaurenceMichael Southgate20 March 2019 at 02:45 #53001
The pressure plate is ready for pick-up, but they are nervous about removing the carrier bearing in case they damage something. Does anyone have any advice for its removal? Apparently there’s a locking ring and it’s this they are not sure how to remove to release the bearing.
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