Is this clutch fork toast?

[ddubois]

I'm installing a new Sachs pressure plate, disc, TO bearing on my 71T. I also have a new fork pivot bolt, cone washer and flat spring. When I install the trans and rotate the TOB into position the fork just rattles around. There is about 5 mm of play between the fork ends and the TOB ears until the flat spring is contacted. I'm wondering if the ball cup in the fork is worn down? I noticed when I took the original stuff apart there was no cone washer on the fork but instead a few flat washers that amounted to about half the thickness of the cone washer, thereby moving the fork ears closer to the TOB tabs.

[Grady Clay]

Originally Posted by ddubois

I'm wondering if the ball cup in the fork is worn down?

I don’t think so but please post more images.

Show some of the bearing surface in the arm, under the ball of the pivot.

Show some of the pivot. I am used to seeing a pivot that has ‘syncro-like’ molly plating on the ball surface.

What is the condition of the ‘fingers’ where they contact the TO bearing?

It would be unusual to find damage at the ‘plastic piece’ end of the arm but you should look. Be sure and use the aftermarket aluminum replacement for the plastic piece. Check that it doesn’t bind against the arm when released or fully actuated.

I assume you are replacing the clutch cable/Bowden tube assembly also.

What is the condition of the cast support ring on the differential side cover?

Is the steel ‘loop’ to support the Bowden tube in place and in reasonable condition?

While the Bowden tube is off the chassis, inspect the firewall bulkhead where the Bowden tube seats against the end of the tunnel. It is possible for the chassis to be cracked there. It is difficult to see. Sometimes it only shows up as slight movement when operating the clutch.



First, you need to bend the finger spring to get proper contact and spring tension. A replacement finger spring doesn’t come ‘ready-to-use’ without some ‘tweeking’.

Where is the arm position in the transmission bell housing opening when lightly tensioned against the TO bearing?

Critical here is that you have sufficient clearance of the clutch arm to the transmission casting (toward the engine) and between the clutch arm and the corner of the pressure plate housing.

It is reasonable to grind away some material on the casting to get a bit more ‘throw’ of the arm. Many have to grind clearance on the arm to miss the pressure plate housing when the clutch is fully operated. I have seen success at 20-30% of the arm cross-section. Be sure to radius & polish the ground surfaces.

Don’t be afraid of changing the thickness of the ‘conical washer’ slightly – either way. The goal is to get the clutch arm in the most advantageous position while clearing the casting and pressure plate housing.

Check to see if you have the original ‘long’ TO bearing guide tube unique to ’70-’71. Too often a PO installs the earlier (shorter) version with poor results.

I don’t see mention of flywheel condition, repair or replacement. A worn, repaired but in-spec flywheel moves the clutch toward the engine and can get things where they work poorly. I recommend a new flywheel and pilot bearing.

The flywheel bolts are generally ‘use once’ and are unique to ’70-’77. The bolts (and 6-hole washer) are different from the ’65-’69 versions so be careful.

While you have things apart, check the fit and slip of the clutch disc splines on the input shaft. I use valve lapping compound to improve the slip-fit. This allows the clutch disc to better ‘float’ when the clutch is released. Be sure to clean any trace of compound and any excess lube.

It is very worthwhile to add the “Dam Seal” mod to the TO bearing guide tube. Search Pelican.

What is the condition at the pedal assembly?

Best,
Grady

[ddubois]

Grady,
Attached are some more pics of the fork. I also included a pic of the old and new pivot bolt. The answer to most of your questions is yes. I'm in the midst of restoring this car and everything related to the clutch is new, including a rebuilt pedal cluster and all new bushings throughout the shift linkage. I did resurface the flywheel and it's close to the minimum at about .38". A new pilot bearing and flywheel bolts were used. I will be installing a new cable/tube including the Weltmeister aluminum coupler that interfaces to the fork arm and replaces the plastic piece.
The trans is off now, but I did notice that when installed the fork arm end was close enough to the engine to concern me that there will be enough room for travel.
Looking at the old pivot bolt there is clearly some galling as well as some scoring in the fork cup. So I'm guessing the fork cup has worn down some and I'm thinking the solution here is to remove the conical washer and replace with an appropriate stack of washers to get the height right (as it was when I took everything apart). The fork tabs that mate to the TOB show minimal wear, so if the consensus is that it's OK to use this fork after I clean up the pivot cup I may go that route. But then again, considering I've replaced everything clutch related, as well as all new seals throughout the trans, I may as well spring the bucks for a new fork and be done with it.