Clutch not quite disengaging

[A TR7 16V]

I'm still looking at how I might fix the worn clutch pedal bracket that's in the car. 

The replacement bracket and pedal arm do take a 5/8 bolt through the pivot - the unthreaded section of the 5/8ths bolt I have is the same diameter as the pin. i.e. 0.616" not the 0.625" I expected. In which case, a 3-1/4 DIN 931 bolt should have an unthreaded section the right length and can be shortened to the right length of exposed thread. It should have 1.5" of thread and 1.75" unthreaded, but the one I have is threaded 1.8" (like a DIN 931 over 6" should be) and only has 1.4" of unthreaded (so is too short). So a proper DIN 931 3.25" or a 3.5" threaded 1.8" like the one I've got at the moment. I don't think it will matter that the 3-1/4 bolt I have will have 3 or 4 mm of thread inside the bush.

So I'm thinking of getting a 5/8ths thin nut welded on one outside of the bracket, and a 5/8ths washer or maybe 2 welded on the other outside. The bolt can then be screwed in so it's tight on the welded on washer, but doesn't nip the pedal; then locked with a second thin nut jammed on. I am wondering if that needs a shaketight washer between them.

If the bush in the pedal arm is no good after being seized on the pin, that will need replacing. But at least they are available.

[Pete Lewis]

there room to mig a washer both sides of the bracket then you just need a nyloc nut to give it a nip

and dont forget to grease it !!!

this problem is typical of no maintenance with an oil can  

some where it should enforce give a squirt to anything that moves  ...the pedals are just out of sight out of mind 

we drilled and added a nipple to the clevis  but having sold the car knowone knows its there  now 

Pete

[poppyman]

There are some shoulder washers that may do the job. They are usually used on exhaust straps.

Tony.  

[A TR7 16V]

3 hours ago, Pete Lewis said:

there room to mig a washer both sides of the bracket then you just need a nyloc nut to give it a nip

Pete

The issue with welding washers on both sides is the one, I think it was Colin, identified of the pin turning in the bracket rather than or as well as the pedal turning on the pin. But maybe shaketights would do instead of a welded nut and jam nut.

Anyway, the replacement is in now, and I can confirm that, in the 1970 13/60 I have, the brake pedal and it's bracket fit where the clutch pedal should go. 

The old set was giving about 5mm of play at the pedal from the wear in the hole for the pin, which is seized in the bush, and another 8 or 10 from the assembly at the joint between the pedal arm and the master cylinder piston rod - a lot of that just from the clevis pin itself (is it meant to wear sacrificially?). The new 5/16th clevis was very tight in the replacement arm, if not so tight in the fork on the end of the rod.

So I think the loss in pedal movement due to slack in the mechanism is less than a 1/4 of what is was. It's enough that, for now, there's no grunting going into reverse.

BTW, has anyone fitted a bigger bore master cylinder, and are there any risks in pushing the slave too far?

Graham

 

Graham

[PeteH]

When I pulled Both the Clutch and Brake pedal/box units out of my "Crate of parts". They where both seized onto the spindle and where rotating on the Flange sides. where they had worn the holes slightly? 1/16"! Oval. I ran some weld into the oval,dressed it back and filed it to a tight fit. Now the pedal works properly again. I am tempted to put a bead of weld on one side to stop it hapening again?. The other option is to "D" the end of the pin and weld a strip over the hole to stop rotation but that will require modifying the pin too. The simple answer might be to drill an oil hole into the pedal, and a squirt of oil, now and again?. I think I like simple?.

Pete

[Pete Lewis]

depends on the cluch travel a aftermarket of 0.75 " will raise the pedal load but they can be very cheap eg landrover based .sub £20

in normal use the slave will be midships in its cylinder so overstroke is somewhat unlikely

orig master on 13/60 brake and cluch was 0.625"

mine was a 1964 and the shaft had a anti rotation flat and remains of a D hole  its obviously got cheaper as time gores by  ha !

all masters must have some pushrod free /end float  to ensure the piston is fully returned and not held by the pedal  a light rattle fit 

Pete

[A TR7 16V]

If you mean STC500100, I see those really are cheap. Will need a fork fitting I see, But even so, that's still cheap. Wonder how much control I get in setting where the pedal sits and goes down to. Is it likely to need a stop on the pedal, or is whatever limits the travel in the cylinder strong enough?

Graham

[A TR7 16V]

1 hour ago, PeteH said:

When I pulled Both the Clutch and Brake pedal/box units out of my "Crate of parts". They where both seized onto the spindle and where rotating on the Flange sides. where they had worn the holes slightly? 1/16"! Oval. I ran some weld into the oval,dressed it back and filed it to a tight fit. Now the pedal works properly again. I am tempted to put a bead of weld on one side to stop it hapening again?. The other option is to "D" the end of the pin and weld a strip over the hole to stop rotation but that will require modifying the pin too. The simple answer might be to drill an oil hole into the pedal, and a squirt of oil, now and again?. I think I like simple?.

Pete

How'd you unseize the pins from the arms?

Graham

[PeteH]

22 minutes ago, A TR7 16V said:

How'd you unseize the pins from the arms?

Graham

Undersize socket on the pin, and an oversize socket on the other side, and my trusty Record vice. Once it moved It tapped out with a punch.

I put it in the lathe and polished the pin with 200 emery.

Pete

[A TR7 16V]

I wondered if it would need some heat, but yours just pressed out. I'll give a try, though my vices are more modest than "Record" ones.

Graham