I am in the process of assembling the clutch to the flywheel, and on measuring the distance from the crankcase flange to the levers, have found it is averaging out at 0.303" +/- 0.013". My centre plate is a B&B which carries the friction material, and according to the Companion, the levers should be set at 3/16". Reading up on the various fixes for adjusting the fulcum levers, I have decided to use the grubscrew repair method, but I have a few questions before I make a start.

• What is the best size grub screw? Threads on this forum mention 3/16" BSF & 1/4" BSF. Doug Woodrow's book refers to 1/4" BSF, and JF Harrington's article in the Companion uses 5/16" BSF. Obviously a larger grubsrew gives a greater area for the lever to bear on, although it does reduce the number of threads fully engaged, but would this matter?

• Does anyone know a supplier for BSF grubscrews, despite lots of Googling, I have only found BSW & UNF grubscrews. UNF would probably be OK (but would mean buying new taps), but I think BSW would be too course.

• Am I right in thinking that the grubscrews should not protrude on the otherside of the clutch cover plate, as they might restrict the amount the pressure plate can lift?

In the same area, I have noticed that there as a fair bit of pedal movement before the clutch withdrawal levers contact the clutch withdrawal collar – i.e. the pedal flops around when not depressed. Should there be a spring or something similar, to keep the levers in contact with the collar?

Thanks in anticipation.

David Offer.

Why not cut a BSF bolt/machine screw off and make your own. A bit fiddly but it would work.

Hello David, I did mine over the winter using 1/4 BSF socket grubscrews fitted from the back. There isn't any point in fitting anything larger as the levers are only about a 1/4 wide and anyway,the contact area is quite small. As you say, the 1/4 BSF gives a reasonable number of threads.
The screws need to be either a tight fit in the holes or to be liberally coated in Loctite Studloc or similar to prevent movement.
Grubscrews can be easily made from threaded bar or screws with the heads cut off or even made by putting a thread on some steel bar. I think though that the socket screws are better as they are made from a tougher grade of steel and shouldn't wear too quickly.
Not too sure about the answers to some of your other questions so hopefully, there will be answers from someone more knowledable than me.

Wrt the 'floppy' pedal, there should be a spring on the outside of the gearbox housing which bears on the pedal shaft and the housing. The purpose of this is to keep the withdrawal collar and bearing in constant contact with the declutching levers. (This is for 3 speed boxes - not sure bout 4 speed boxes).

David,
I've done this a number of times, its my prefered method. I use 1/4UNF to get the slightly finer thread and cut down a socket head screw with a hack sawed slot for the screwdriver. I sense when cutting with a hack saw that socket screws seem to be slightly better material than ordinary HT bolts (and I have a ready supply!). Make sure they're a reasonably good fit in the female thread - not flopping about, glue in with Loctite and also centre pop the back to tightly grip the thread. As said, don't let them protrude, if you did find some grub screws they'd probably be too long and a cup point to boot - you'd have to trim it down anyway (slot a nut and grip in a vice rather than tighten onto the thread). They need to be about 1/8" to 3/16" long.

Setting up is a lot of trial and error, I've always fancied making a set up jig like the Austin tool to be able to adjust the screws directly but never got round to it. The important thing is to get all three levers at the same height. Only use 3 or 4 springs while you're fiddling about and only put the full set and mouse traps in when finally done. Always keep the parts in the same rotational position to each other, it shouldn't make any difference but its easy to match mark up and do it that way!

I've only set up for a 4 speed box and set up the levers to be almost flush with the crankcase to gearbox flange. Set the pedal lever to bring the release bearing just short of the three levers holding the release bearing forward with a screw driver while the pedal bolt is tightened. This is all best done with the gearbox out of the car and checked as an assembly before the engine and box go back in.

I hope it works for you!

Dave

1/4BSF socket grubscrews in 1/4" & 3/8" length are available from:-

www.metal2models.btinternet.co.uk/grub.pdf

Derek

Thanks for all your help. I have now ordered grubsrews and the correct tapping drill from the metal2models site, just have to wait for them to arrive. I also found some spare 1/4" BSF manifold studs, so will see how they compare to the grubsrews & use whichever seems the hardest. I'll let you know how I get on.

Old thread, but relevant nonetheless.

One question - when do apply the Loctite?

If you use it before setting each grub screw, don't the adjustments break the Loctite seal? On the other hand, once each grub screw is in its correct position, it would mean marking them and removing them, coating with Loctite and then trying to get them back to their correct setting.

John, Studlock or Screwlock does not go off immediately so there is time to adjust and, if it does go off the screw can still be moved into its final position. Just don't leave it for days.

Location: Near M1 Motorway Jtn 28

Or you could use one of Loctite's wicking thread sealers which can be applied to a fastener in situ, eg loctite 290. Can be hard to find in affordable amounts, though.
Regards,
Stuart

Although e bay item no.172391608701 isn't too bad pricewise though apparently cheaper from Hong Kong!

S.

I have made up a strap to bolt across the flywheel housing which allows you to check the gap using a piece of 3/16 plate and feelers.
I measure the depth to the grub screw and usually file it down making a note of the distance moved.if i remember correctly .005 of the grub screw makes .020 difference at the end of the lever.If you get them all level it makes the clutch operation much smoother.
This strap also has a hole in the centre which also centralizes the clutch when you finally assemble it.

Many thanks to all of you for your help.

Now I feel ready to proceed.

John

This seems good price, but maybe label suggests not genuine.

John,

Bearingboys have 10ml Loctite 290 at £8.58 inc vat

http://www.bearingboys.co.uk/Threadlocking/Loctite-290-High-Strength-Penetrating-10ml-837-p?gclid=CKnw866eldACFYdAGwodXBUH_w

Jeff.

Location: Almost but not quite, the far North East of England

Location: Shropshire

As for the question of the floppy pedal, I thing David Armstrong has the right answer here. If the release bearing is in constant contact with the levers, that bearing will be running all the time and getting prematurely worn out. Best to have a minimal amount of free play before the levers contact the bearing.

Location: Wellington NZ

On 3-speed gearboxes the thrust race carrier has slots that engage with the clutch levers so the race turns all the time. There is a spring on the outside of the gearbox that bears on the pedal and keeps the levers in contact all the time so the pedal should not be floppy.
On 4-speed gearboxes there is a spring on the inside pushing the thrust race away from the levers and mouse-trap springs holding the levers away from the thrust race. There is no spring on the pedal so as far as I remember it is floppy.
The grubscrews used to adjust the levers should not protrude on the engine side. If they do it reduces the amount of clutch travel. I also find that grub screws often need the face to be ground flat where they bear on the levers. They usually have a raised ring for when they are used to locate items onto a shaft.

Being beyond the sell by date isn't necessarily a problem - it depends on the product.
I have bottles of Loctite 'Retainer 601' and 'Bearing Fit Compound 641' that are about 45 years old and still good!

This is something that is 'known' in the engineering/machining trades.
I would suggest if anyone is worried about the product they speak directly to Loctite themselves or a retail firm such as the Bearing Boys in the first instance.
PS Thanks John Mims - I've just ordered some!
Steve V.

Location: Polegate, East Sussex, United Kingdom

Thanks to Jim Holyoake for explaining the difference between the early and late clutch arrangement. I did have a 1929 A7 but only for a month or two and never pulled it apart, so I didn't know there was such a difference.

Location: Wellington NZ