Clutch Pedal Vibration

[Hedd_Jones]

Sometimes the toggles can hit the taper pins on the pedal shaft. Generally this happens if the spring that holds the levers against the spigot bearing is broken. The spring is the one against the pedal where the shaft goes in the gearbox.

[John P]

I’ve been having another thought about this issue and now wonder if the vibration could have been there before but didn’t create the rattling of the clutch pedal.

When I started all this one of the things I was trying to achieve was to get more clutch disengagement which was achieved by reducing the previously excessive clearance between the toggles and the thrust race.

So, if before I did the refurbishment the clutch pedal was as far forward as it wanted to go under the force of the pedal spring but was still not really contacting the thrust race then I suppose any vibration coming from the race wouldn’t have been transmitted to the pedal.

If I run the engine and pull the pedal slightly upwards the rattle certainly seems to stop which suggests this could be what’s happening but I still don’t know what to do about it.

Has anyone here reworked a 3-speed thrust race housing? On line I’ve seen vague comments about building up the lugs where the pedal shaft arms bear with bronze and also fitting a ring in the housing where the toggles rest (presumably this would need to be hardened) but I’m still reluctant to take the engine out again unless I know what the options are once I’ve done so.

[Terrytuned]

Best option is to fit a 4spd bearing conversion, since our first special threw all the ball bearing out at a hill climb which was 25yrs ago have never use a 3spd bearing.  Terry.

[Hedd_Jones]

When I first had a 3speed car father and I set it up. It was no bloody good, the pedal was nearlynon the floor and barely disengaged.

I had the car in the midlands when it was painted, and it was down to me to fix it. Engine out, box off job.

I spent ages with a straight edge and a caliper working out where everythig was, and where it needed to be, so that the pedal was suitably high to allow full disengagement, but with sufficient slop to allow the plates to wear without early slip.

I should also say that the clutch components were, except for the linings all 'used' and fairly sloppy, the clutch bearing, the only one in stock at the time had the usual heavy wear where the toggles beared.

I settled on a toggle lever setting that had the rearmost part of the toggle (that bears on the clutch bearing) to be 6mm from a straight edge put against the bell housing. I think my calculations gave me a working range, and I had a 6mm drill to hand which was in the range, and could be used as a simple 'go-no go' gauge.

Having had the issue where the taper pins in the clutch pedal shaft had hit the toggles (and bent one), I concluded all this buisiness of shimming the clutch bearing, or filing the toggle pivots was pure bodgery as it would mean that the toggles would not be in the position Austins intended, and may therefore mean that other problems manifedted themselves. I therefore bent them to suit (which seemed to be the Austin recommended way). On a 3 speed car this is easily done, I used an oxy propane torch to get them to cherry in situ and bent using a hammer with care. The clutch is easily wedged with a well placed screw driver, and the toggle should spin around which means you can bend it the other way. I quenshed with a wet rag. The toggles are simply adjusted thus in less than 5 minuites, with the clutch fully assembled. The only other pointer is that if you have worn components (like mine), you need to make sure you get the slop out of the toggle (by pressig it down hard) when you measure your setting. And they really do need to be set equal.

I've since repeated this on every 3 speed clutch I have set with no issues at all. Dad let me have an engine vince Leek had built for him, it came ready ro fit with clutch gearbox etc. For transport I took the box off and for interest checked the toggle settings. I recall it was in the region of 7mm so I was happy. Its still in the car now.

The clutch release bearigs are also simplicity itself. david Cochrane has some races made up, and I have fitted one. Whilst there was nothing wrong with the product, I didnt find it solved the problem I had, which was noise. That was solved by fitting the proper cover over the oiling hole!.

Fundamentally the clutchnis simplicity itself. Pedal vibration is one of 2 things. Uneven pressure on the toggles. Or the toggles twatting something as the go round.

[Steve Jones]

Whilst I now use four speed races using the modifications Terry shows, I have, also, re-worked three speed races in the past. My way has been to weld up the area of the cage at the bottom of the slot where it wears and then face it up again in the lathe. It's worked OK. However, in re-setting all the components, you have to be careful that the levers don't hit the taper pins in the cross shaft as others have already said. I did have this happen to me once on a trial after a particularly difficult stop/re-start when something or other moved (we never did work out what). Pressing the pedal slightly caused the resulting noise to go away so, as a temporary fix, we hooked a bungy strap between the pedal and the dynamo and completed the event. Something certainly to check.

Steve