Clutch

I have a '62 Healey and the clutch is just releasing enough to be able to shift gears, although it sometimes grinds a little, especially going into reverse. I know there is no trapped air in the fluid lines or in the slave or master cylinders, and both are working correctly. I suspect the problem is inside the clutch housing because when I disconnect the slave cylinder push rod the clutch fork has a lot of play in it. Looking for a heads up, I was wondering if anyone has ever experienced this and what they found. This will be my first time pulling a transmission and replacing a clutch, and looking at the diagram I'm wondering if the release bearing retainers (one or both) maybe have "come off" causing the release bearing to only partially "engage". Whoever put the last clutch in made a slave cylinder push rod that is approximately 3/4" longer that the standard rod to get the clutch to release, which it barely does. Any thoughts would be appreciated.

Regards,
Bruce

More likely, is that the graphite throwout bearing has worn down beyond use.

Hardly mentioned (anywhere) anymore, but when I purchased a new 1973 MGB, I was cautioned NOT to hold the clutch down any longer than necessary. In other words, any time you come to a stop, or are sitting waiting for a line of cars to turn left, slip it into neutral and take your foot COMPLETELY off the clutch. The same goes for "riding" the clutch while underway__get your foot away from it.

Not to say that you're guilty of such, but taking an opportunity to point it out; these t/o bearings are a wear item, and ideally, you wouldn't want to be forced into doing a clutch job, until the clutch itself demanded it

Before you get into removing the trans, check for wear on the clevis pin under the dash. It does not take much of a grove in the pin to give less throw to the clutch. This is a one dollar part that is very often overlooked ( and thick grease the replacement).
TH

Another possibility is it's the wrong throwout bearing for the clutch that's installed. Moss carries three different bearings - one for each of the three clutch designs. That could account for why a PO installed a longer pushrod.

There could be wear in the pedal clevis area, but IMHO that's not the problem because that wouldn't have anything to do with the play in the clutch slave/operating lever area as described above.

Thanks for the good info. I'll try to update when I have found what the problem turns out to be but I'm guessing I'll at least find a worn throwout bearing. Since while I've got the tranny out I will probably replace "everything", any ideas on the best brand to use, and specifically if anyone would recommend a roller-bearing type release bearing?

When you get the tranny pulled back and if you have a pilot tool, you could undo the clutch bolts and measure the diameter of the disc. They came in 9", 10" and 9-1/2". Call Moss tech support and ask for the release bearing to suit your disc. Note - if your clutch has the diaphragm spring it's the 9.5".

Not sure there are any choices for the type of release bearing, but if you're a typical Big Healey owner, would think it would last a lifetime.

Reminds me of my old girl, the clutch eventually started to slip so the gearbox was removed and a whole pile of trouble was revealed.

The bushes to the fork assembly were worn

The throw out bearing was worn - on one side only :blue:

A spring in the clutch housing was broken - resulting in the odd wear to the bearing.

Replaced all the worn parts and installed a rear crankshaft seal and a seal in the rear of the bell housing at the same time and everything was tickety boo after that.



Bob

As a follow-up, I pulled the transmission last week and found that the release bearing was in fact worn. It was actually worn into the metal - I was lucky to have be able to put it into gear at all. Since the tranny was out I decided to go ahead and install a new disc and pressure plate and a replaced the clutch fork shaft as there was a little bit of play there. I also installed the correct-length push rod for the slave cylinder. The clutch pedal now goes all the way to the floor and releases where it should. It sure is nice to have a properly working clutch! Thank you all for your suggestion.

Not sure there are any choices for the type of release bearing, but if you're a typical Big Healey owner, would think it would last a lifetime.

YEP Steve there are specific bearings for each clutch type and the carbon element in these bearings will not last a life time see Rand's comment.

BruceAllcorn said:

...specifically if anyone would recommend a roller-bearing type release bearing?

Click to expand...

Keoke,
I was referring to this when I said I didn't know if there were different types of release bearing. Was thinking if one replaced the bearing as part of a clutch overhaul on a hobby Healey driven a couple thousand miles a year by an older driver -- then it would probably last a lifetime. Maybe not even then, eh?

Someone--one of the Blighty companies, I think--sells a ball (roller?) throwout bearing for Big Healeys.

Keeping your foot off the clutch pedal until it's needed to get the car underway, or to swap a cog, serves the same purpose of having a lifetime release bearing. In a little over forty (>40) years of continuous British sportscar driving__and graphite throwout bearings__I've never pulled one out of my own cars that showed even moderate wear.

For myself and countless others, the standard issue graphite throwout bearing is already lifetime.

I never wore mine out in ten years on my 100, but I think I swapped in an NOS one when I did the clutch, I do know they don't last very long on Sprites, but it is a smaller piece with less surface area.

As a footnote, when I replaced my throwout bearing I replaced it with a graphite-type from Moss. I had e-mailed Dennis Welch and they have a bearing-type throwout bearing for my Healey, but they advised that the center section of the pressure plate (that the graphite-type contacts) had to be removed. This meant that the bearing-type contacted the "brackets" that held the center section which I presumed would mean metal to metal contact. However, not wanting to wait for the bearing-type to get here from England, and not to sure I wanted to modify the pressure plate, and because the bearing-type sold for something over 100 pounds, I went ahead and put in the graphite-type. I understand that all new cars with clutches have the bearing type, but I also believe what has been stated here that, used properly, the graphite-type will last longer than I will.