Jump to content

Recommended Posts

Hi Folks,

not sure if I have posted this before. This is my clutch fork taper removed from the 4A. No cross pin fitted.

It had done apprx 40,000 - 50,000miles since fitting (May '16). Apparently this was a good quality pin !!!:o

The crack is the wiggly black line in the middle of the shank.

 

Roger

P1060772a.jpg

Link to post
Share on other sites

Hi Marco,

I bought a Saab 9.3  Hydraulic co-axial clutch the other week to try and understand what is going on. It may not fit but they are not expensive.

 

Hi Iain

the problem is not the quality of the pins but the special design of the shaft/fork/pin arrangement.

'IF' the mechanism truly did work in a shear force situation then the pin would never fail. Even a HB pencil would work - perhaps not.

However the smallest amount of tensile or torsional load will start the rot from day 1.

I get my pins from either Moss or the TRShop but I would not complain about their service. It is the design.

My TR4 has had the fork modified so that the pin is in double shear so this (and its better fit) will eliminate failure (probably - I haven't done many miles with it)

Marco's co-axial slave is the answer. There are proprietary ready to run units on the market but the fun is to make your own.

Marco did a lot of measuring and fitting and ended up with a beauty. I would like to go for it my way. Sadly I haven't a map and not sure where I'm going.

 

In the mean time - fit a roll pin at 90 degrees

Roger

 

 

 

Link to post
Share on other sites

Roger,

You have answered my question, you have a modified fork so that it is double shear.  I have two roll pins as well as the taper pin in mine.  The simple fact is that the load will follow the stiffest path so any play in any secondary fixing will mean it doesn't see any appreciable load until the primary fixing has failed.

Rgds Ian

Link to post
Share on other sites

Hi Ian,

indeed the tightest fit will take the load. Given time that fit will relax slightly and hopefully more than one pin share the load.

With the OEM design if (and it is a big if) the taper fit was absolutely spot on then the pin would be up for it.

But as we know repro fits and tolerances are not what Armstrong or Whitworth would have wanted.

 

Roger

Link to post
Share on other sites

Hi Peter,

Before I left the worlds #1 airline I did a stock take.  I don;t think I will run out unless I do a full NDT of the RB211 I borrowed.

I was interested in seeing what a concentric slave looked like close up. 

Somebody mentioned on the Sideways forum about the 9.3 slave - but that may have been for a GT6.  It will not go to waste as I have a Saab 9.3 (I love it)

 and I may just fit another one to it.

It looks on the small side for the TR box; but I haven't played with it yet.

 

Roger

Link to post
Share on other sites

I cant wait to jump on the from the Hydraulic concentric clutch bandwagon,  so really looking forward to what you learn from the Saab unit - keep at it.  I followed Marco's project with interest but it was maybe a challenging approach and the units he used are difficult to source. 

Cheers,

Alf 

Link to post
Share on other sites

Hi Roger,

sadly the TR gearbox shaft diameter is for a tractor and not from a car, its diameter on the splines is about 32 mm!!!!

The hydraulic unit for the Saab 9.3 seems to have a 34 mm piston, it's very likely you don't get it over the gearbox shaft.

Bleeding also seams a problem to me with this unit. But I hope you tell me I'm wrong!

The Sachs unit 318 265 4206 unit I used is for Opel / Vauxhall Omega and has a 35 mm piston, this fits with modifications.

This unit is also very easy and for very small money (€50) avivable, I will use it again for my MX5 project.

I found some with bigger pistons and more from Mercedes small trucks, but for some 100 of Euros.

Wishing you much success.

Ciao, Marco

 

Link to post
Share on other sites
1 hour ago, Bob Smith said:

I have a couple of original unused Stanpart taper pins 158777 if anybody needs one. I no longer have a need for a spare pin as my TR has been sold.

That would be a great trial project. To make a rig that would actuate the clutch 50,000 or 60,000 times in a few days or so to see when the pin failed.

But were the OEM shafts and forks better than today.  rather a lot of variables.

 

Roger

Link to post
Share on other sites
10 hours ago, Z320 said:

Hi Roger,

sadly the TR gearbox shaft diameter is for a tractor and not from a car, its diameter on the splines is about 32 mm!!!!

The hydraulic unit for the Saab 9.3 seems to have a 34 mm piston, it's very likely you don't get it over the gearbox shaft.

Bleeding also seams a problem to me with this unit. But I hope you tell me I'm wrong!

The Sachs unit 318 265 4206 unit I used is for Opel / Vauxhall Omega and has a 35 mm piston, this fits with modifications.

This unit is also very easy and for very small money (€50) avivable, I will use it again for my MX5 project.

I found some with bigger pistons and more from Mercedes small trucks, but for some 100 of Euros.

Wishing you much success.

Ciao, Marco

 

Hi Marco,

the 9.3 diameter was noted immediately it came out of the box.  But that is not a problem. There tends to be a lot of waste in R&D.

It gives me a feel for the project simply to have something solid in my hands.

I'll investigate your Sachs unit and see how it develops.

 

Roger

Link to post
Share on other sites
19 hours ago, RogerH said:

Hi Peter,

Before I left the worlds #1 airline I did a stock take.  I don;t think I will run out unless I do a full NDT of the RB211 I borrowed.

I was interested in seeing what a concentric slave looked like close up. 

Somebody mentioned on the Sideways forum about the 9.3 slave - but that may have been for a GT6.  It will not go to waste as I have a Saab 9.3 (I love it)

 and I may just fit another one to it.

It looks on the small side for the TR box; but I haven't played with it yet.

 

Roger

You could alwys fit a saloon box with its smaller input shaft.

Rgds Ian

Link to post
Share on other sites

I know you all like a project and this may sound a bit stupid but if the pins are the weak spot why not fit the pin and braze/weld the fork to the shaft. If the bushes fail (not looked at my box to check) can the shaft be pull back inside while the bushes are replaced or will the input shaft prevent this?

Feel free to say I'm talking C....!!  

Tin hat on.

Andy

Link to post
Share on other sites

Hi Andy,

one of the repairs carried out when you are on the road is to pull the GB back a touch and then weld the shaft insitu.

When you need to sort it out proper you need to cut the shaft.

So much easier to support the taper pin with another method.

 

Roger

Link to post
Share on other sites

The concentric  clutch method is obviously the ultimate solution, however I am a believer in keeping it simple with as many original parts as possible and a kit which could solve the problem and be fitted by the average home mechanic would be ideal.

To this end the following may be worth considering

1. Fix the fork by the normal method. 

2. Cut the cross  shaft about 3ins pertruding from the fork on LH (lever side). 

3. Weld or braze the fork to shaft. 

4. Have a machine shop produce a sleeve with 2 inch long internal splines, a split end and a pinch bolt. and cut mating splines on the remaining rh half of the shaft. Weld sleeve to cross  shaft next to fork, or cut splines and clamp. 

The RH half could be assembled from the inside outwards and the LH side could be slid in from the LH outside as normal, pushed into the female splined sleeve and clamped up. 

Chris

 

 

 

Edited by ChrisR-4A
Link to post
Share on other sites
3 hours ago, ChrisR-4A said:

The concentric  clutch method is obviously the ultimate solution, however I am a believer in keeping it simple with as many original parts as possible and a kit which could solve the problem and be fitted by the average home mechanic would be ideal.

To this end the following may be worth considering

1. Fix the fork by the normal method. 

2. Cut the cross  shaft about 3ins pertruding from the fork on LH (lever side). 

3. Weld or braze the fork to shaft. 

4. Have a machine shop produce a sleeve with 2 inch long internal splines, a split end and a pinch bolt. and cut mating splines on the remaining rh half of the shaft. Weld sleeve to cross  shaft next to fork, or cut splines and clamp. 

The RH half could be assembled from the inside outwards and the LH side could be slid in from the LH outside as normal, pushed into the female splined sleeve and clamped up. 

Chris

 

 

 

That's keeping it simple?  Cheers, Bill.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.