That was a year that was..

[trchris]

Hi Pete

Nice to see you enjoying yourself I find the clutch on my 4a is a little stiff the previous owner fitted a new one some 25 years ago and did very little miles which didnt help the only cure is probably a change to Laycock when the time comes. How's the overheating problem? nothing major I hope

Chris

[Bfg]

1 hour ago, BRENDA1 said:

The clutch used to be very heavy and hard to push down on Brenda...  it was right down at the to the floor and only had to lift 1/4 before it engaged, when I did the gear box repairs I changed the complete clutch assembly from Borg & Beck to a Laycock assembly this is now much lighter on the left leg,

Mike. Redrose Group 

I've checked the receipt, from the TR shop dated 15/07/99 and that shows  GCK6003X - CLUTCH KIT TR4A-TR6  £85 + VAT = £99.88.   That part number is for a Borg & Beck 3-piece kit.  1999 was when the car was put back on the road and it has done almost 38,000 miles over those 20 years.  I don't know how long a clutch might last in TR4.  

 

[Bfg]

29 minutes ago, trchris said:

Hi Pete

Nice to see you enjoying yourself I find the clutch on my 4a is a little stiff the previous owner fitted a new one some 25 years ago and did very little miles which didnt help the only cure is probably a change to Laycock when the time comes. How's the overheating problem? nothing major I hope

Chris

Cheers Chris,

Having taken the thermostat out and not yet replaced it, there's no issue with overheating, but then I haven't been far either, just 5 miles yesterday.  She still piddles a little from the expansion bottle, which is something I'll look into sometime soon.  And there was emulsified water deposit on the underside of the rocker cover filler cap but nothing around the valve gear when I peered in, so we thought it was probably just from atmospheric condensation. The breather is from the rocker straight to ground.   

Pete.

[Lebro]

That's a diaphram clutch, so friction plate is probably worn.  As for how long they last - it all depends on how it is used. If it is used to hold the car on a hill etc, then the answer is not very long. Same with release bearings (although not the current problem) if the driver sits stationary in gear with foot on clutch, then the bearing will wear out more quickly than if he (or she) had selected neutral, & put the handbrake on.

(one of my little gripes about how a lot of people use their cars !)

Bob.

[Bfg]

Katie 's PO is older than myself and doesn't look like he'd be able to hold his foot down on this clutch for very long.  Of course 20 years ago when he first restored her - things might have been very different. 

[Bfg]

piccies taken in the drizzling rain . .

There's a spring dangling which I guess might have been a return spring on the clutch pedal (?). It's loop at the bottom is broken off. 

The clutch master cylinder looks to be 3/4" (spotted by Rich) according to the cast into the reservoir's side). I haven't yet looked up what was standard for the late TR4A.   Double drat ..my Moss catalogue is in storage..  I wonder why the clutch pipe is a larger diameter than the brake pipe.?

I cannot see any size markings on the slave cylinder, but I think it's fitted on the wrong side of the gearbox plate (thanks again to Rich for suggesting that possibility). The workshop manual p.2-106 fig.6 shows the slave cylinder to be mounted on the engine side of that plate.  I don't know what difference that positioning would make to the feel but surely the clutch lever's tie rod would be too long as is, or too short if the cylinder were moved forward to the other side of the gearbox plate.?

^ the slave cylinder's tie-rod fork end appears to be correctly positioned to the centre of three holes in the release bearing's lever arm, and naturally lubricated. Again there is no spring to add to the weight of the pedal. 

As said previously I believe the car is fitted with a Borg & Beck diaphragm clutch. 

Edited March 10, 2021 by Bfg

[stuart]

The clutch pipe is always 1/4" as opposed to 3/16" brake lines to save confusion. The spring on the pedal and the spring on the slave wont help the heaviness of the pedal but the angle of the actuating lever does rather lead me to think that the pin has gone on the clutch fork hence why the slave cylinder is on the rear of the mounting plate as it should be on the front face, gearbox out job Im afraid.

Stuart.

[Bfg]

ooh !    Thank you.,  but ooh !

 

 

[Bfg]

2 hours ago, stuart said:

the angle of the actuating lever does rather lead me to think that the pin has gone on the clutch fork

Brilliant - and again Thank you Stuart,  the fork swiveling on the actuation shaft would indeed give the symptoms I'm experiencing with this clutch.  I've booked the car in, subject to space availability, for next Thursday to lift the gearbox out and to address the issue.

I have a new Borg & Beck clutch in stock (bought for the engine I was rebuilding / have yet to finish rebuilding) so that's good to go.  I'll now spend some time going through the archives to read all about these clutch-fork pins, so that I might get any other parts or tools we'll need ready and in stock for then.   

Timely advice - Very much appreciated.

If it is the case that the forks have swiveled - does the clutch fork pin usually shear off completely - rendering the car undriveable, or is likely to stay as it is for a while. ?   

cheers, Pete.

     

[james christie]

Hi Pete, the answer is that you can drive for a remarkably long time before it goes completely, but the angst takes the fun out of it. You will find that the bit of pin that is left does just operate the clutch - as you have found  - but destroys the shaft.

When you put it all together again, the advice is to drill and add a split cotter pin or bolt as a second fork/shaft fixing.

james

[Ian Vincent]

And if you are unlucky, like I was, you will have to hack saw through the old shaft to get it out. 

Rgds Ian

[Bfg]

Thanks gents,   

With the change in driving position - I cannot say that it is getting worse (pedal closer to the bulkhead) but it feels like it.

So I'll only drive the car down to the container (my outdoor workshop) and keep its mileage and clutch use to the very minimum. I'll also have to be prepared for it to go all together, if that broken pin does not bite into the shaft.

I'll add a replacement shaft to the shopping list.. just in case.  

Preliminary shopping list (as proposed by our TSSC AO., Colin)  ;

• new pin  ..question is what type and whether oversized / hardened ?
• extra roll pin mod to the carrier,  or second bolt at 90 degrees ?
• new cross shaft bearings .. to double up, or get the wider version from Chris Witor.?
• cross shaft ..just in case the old refuses to come out and needs to be cut.
• replacement fork
• replacement bushes for the fork ..round or square.?
• spare bearing carrier,  in case mine is worn
• New clutch kit (which I already have).
• Change of gearbox oil while its out ..what about the overdrive ?

He also suggested drilling a hole in bottom of fork hole, so you can drift out the next broken pin more easily.!

And I might add

• speedo cable, as the speedo is very sluggish and then bounces around at 70mph
• speedo cable 90 degree drive ?

As I am already committed to Borg and Beck, is there any way I can improve its action / lessen the weight ?  ..after all you guys have said change to Laycock.!

Advice and guidance invited.

Anyone with parts ?

Thanks again,

Pete.  

[Lebro]

      

The bolt which often shears has a square head, & is tapered, these are available from any of the usual suppliers.

(There is one in the third photo sitting on top of the machine vice.)

I used an M5 high tensile cap head bolt & nut to act as a backup.  3rd photo shows drilling a hole for the purpose of drifting out a broken bolt.

Bob.

Edited March 11, 2021 by Lebro

[BlueTR3A-5EKT]

15 hours ago, Bfg said:

Brilliant - and again Thank you Stuart,  the fork swiveling on the actuation shaft would indeed give the symptoms I'm experiencing with this clutch.  I've booked the car in, subject to space availability, for next Thursday to lift the gearbox out and to address the issue.

I have a new Borg & Beck clutch in stock (bought for the engine I was rebuilding / have yet to finish rebuilding) so that's good to go.  I'll now spend some time going through the archives to read all about these clutch-fork pins, so that I might get any other parts or tools we'll need ready and in stock for then.   

Timely advice - Very much appreciated.

If it is the case that the forks have swiveled - does the clutch fork pin usually shear off completely - rendering the car undriveable, or is likely to stay as it is for a while. ?   

cheers, Pete.

     

You can test for pin shear from under the car.

Disconnect the slave push rod.

By hand push the lever fully rearwards as disengaging.  then push the lever fully forwards.  at the point of first resistance as the release bearing touches the gear box, keep pushing and a bit more movement will be felt.  That is the slack around the broken pin being taken up as the fork rotates on the shaft.  The pin should not allow any rotation on the shaft.

Fixes involve.

Pin replacement

Pin replacement + additional cross pinning (best method)

Welding.  Works if you are in the 'Desert' with no spares.

Think about renewing the bushes that support the cross shaft while you have it in bits.

Cheers

Peter W

[james christie]

It’s worth replacing the two nearly inaccessible (when the gearbox cover is back on) grease nipples at either end of the cross shaft with ‘remote’  nipples on flexible hoses, which make life a lot easier.

Of course I forgot to do this when I had it all apart a year or so ago........

james

[roy53]

Pete's advice is good as always.

I had this kind of problem once where the opinion was a broken pin. 

I checked out all options first and found changing cylinders solved the issue. Not air in the system but a slight weeping under pressure [ i guess ] no noticeable leak.

You have to reposition the slave .

Roy

 

[Bfg]

1 hour ago, james christie said:

It’s worth replacing the two nearly inaccessible (when the gearbox cover is back on) grease nipples at either end of the cross shaft with ‘remote’  nipples on flexible hoses, which make life a lot easier.

James, can you point me to picture of what you are referring to as I only know of angled grease nipples.

Thanks, Pete

[BlueTR3A-5EKT]

13 minutes ago, Bfg said:

James, can you point me to picture of what you are referring to as I only know of angled grease nipples.

Thanks, Pete

Does your car actually have grease nipples on the ends of the cross shaft?   I thought they had been deleted by the time TR4A arrived.
Peter W

 

Edited March 11, 2021 by BlueTR3A-5EKT

[Bfg]

3 hours ago, Lebro said:

      

The bolt which often shears has a square head, & is tapered, these are available from any of the usual suppliers.

(There is one in the third photo sitting on top of the machine vice.)

I used an M5 high tensile cap head bolt & nut to act as a backup.  3rd photo shows drilling a hole for the purpose of drifting out a broken bolt.

Bob.

Thank you Bob, it's very useful to see what I'll be up against. 

1. I've read that someone used a 3/16 x 1" roll pin but found it a little short and so recommended 1-1/4" long. So might I presume your M5 high tensile set screw was 38 - 40mm long ?
2. And unless i'm unlucky and cannot get the shaft out, then replacing the shaft &/or fork arm ought not be necessary. ?
3. Moss show extended bushes, which look to be copper pipe. Is that the way to go or is it better to double up on the standard type bushes ?
4. as I have no return spring fitted to the outside lever arm, then I ought to get and fit one, along with its little multi-hole anchor plate ?

Cheers to all for their input.

 

[Bfg]

20 minutes ago, BlueTR3A-5EKT said:

Does your car actually have grease nipples on the ends of the cross shaft?   I thought they had been deleted by the time TR4A arrived.
Peter W

 

I've just been told not, and as you say the 4A was without the grease nipple.  

I've also read in another topic, thank you Roger, that the spring (15) and end bolt (18) & (19) are not required, because the fork arm centralises the shaft.

Persons have suggested the Laycock offers a lighter pedal, but I'm already committed to Borg & Beck, is there anything I might do to lighten its action ?  Would changing the 0.75" master cylinder for a 0.70" make a noticeable difference ?  

Pete.

Is special grease required during assembly ?

 

[Lebro]

Sorry I can't remember the length of the M5 screw.  Correct, if you can get the fork to slide off the shaft then no need to replace.

I bough a pair of shaft bushes, & simply drifted them into the hole from the outside, pushing the old ones further in, where they won't do any harm, & still help to support the shaft.

Opinion varies about whether fitting a return spring to the slave cylinder is a good or bad thing. With the old style coil spring type clutch you generally had one to pull the release bearing away from the clutch mechanism to avoid wearing the bearing out.

With the advent of diaphram clutches it became more usual to not have a return spring, & let the release bearing gently touch the clutch fingers, which keeps it spinning. The theory being that the fingers then won't wear out when they repeatedly contact  a stationary bearing. The main benefit to not having a spring is that the clutch free play is self adjusting.

Personally, I have a diaphram clutch , but retain the spring.

Bob.

Edited March 11, 2021 by Lebro

[Bfg]

Thanks Bob, I'll get the spring and try it, and if it don't make me happy it might fly off !

[james christie]

4 hours ago, Bfg said:

James, can you point me to picture of what you are referring to as I only know of angled grease nipples.

Ha! Apparently your modern car doesn’t have them. Indeed I have the angled ones on my 3A which when tightened up point in every direction but the right one, hence my suggestion of the remote ones. Unfortunately there ain’t enough thread to adjust, where they point, with a washer

james

[Bfg]

Ha !  They don't build em like they used to !

  Do you know that you can get 90 degree heads for grease-guns

 

[james christie]

I don’t think you can get any of those grease gun couplers to access my/the grease nipples.

What I had in mind dates from my experience with BIG construction machinery which often uses a grease nipple on a flexible hose a-dangling down to a reachable position!

james