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MG Midget and Sprite Technical - Clutch biting point Midget 1500
I have replaced all clutch components on my '79 1500 (master and slave cylinders, clutch hose, clutch plate, housing and thrust bearing)and I have even managed to bleed the damn system to get a nice firm pedal action (it took lots of time any many expletives!). The only issue I have now, is that the biting point is only an inch or two from the floor, is this normal or have I missed something? I must admit that I have used a pattern part master cylinder / slave and also that I used a slave pushrod pushed fully home in the slave cylinder when bleeding to try and avoid air in the system. Could either this or slight differences in the new parts (length of master pushrod for example)cause the biting point to be so low? and what could I do to alter the biting point so that it bites higher up the return travel of the pedal?
Apart from this biting point issue, the clutch works fine and gear selection is the same as before I changed everything (i.e. very good)
Any wise words or thoughts would be most welcome.
|If I remember correctly, there is no adjustment in the biting point. It all hinges (no pun intended) on the position of the master cylinder, so if you're using a non standard part then that probably explains it.|
Where did you pick up the new hose from? This is the only part of my clutch system I have not replaced?
|C L Carter|
I had the same thing when I replaced various clutch bits on my 1500. The cure I used was to wedge the clutch pedal all the way down to the floor, leave it overnight and in the morning the biting point should be back to where you want it.
|<<the biting point is only an inch or two from the floor, is this normal or have I missed something? >>|
That is quite normal with a new clutch. As it wears, the biting point will get higher.
|Thank you for the comments, I will certainly try the old wedge on the pedal overnight, although if the biting point gets higher with use over time then I needn't worry too much as it is perfectly useable, I was just disconcerted as the biting point was worryingly close to the floor.|
The clutch hose can be purchased from Sussex Classic Car Parts, follow the link below.
The clutch hose isn't cheap but it is well built and comes with all the fittings pre-assembled to it, so no messing with trying to get the flexible pipe over the master and slave nipples like with the original red clutch hose piping.
|The whole point of a hydraulically operated clutch is that it is self adjusting - within limits. The slave piston, hydraulic connection and the master cylinder piston are only pushed back by the cover plate springs. So they should then stop, ready primed for the next time you press the clutch pedal. As the driven plate wears the pistons operate over slightly different lengths of the bores but still travel through the same distance when the pedal is pressed, and this is how they are self adjusting. The only thing that upsets this is either excessive wear in the mechanical pivots or in the driven plate or thrust bearing. As yours is a new clutch if the bite point is low, it either still has air in the system, or the pivot points are worn. There is nothing else!|
PS - an afterthought - add a bent brake pedal to that list of possibles!
|I hope you have checked and rectified any slop in the MC pushrod clevis, the only thing you can control.|
A new clutch will have a bite point just above the floor, and it will gradually rise as the thing is used. This is because the cushion wafer in the driven plate are now very wavy, but will flatten out as they get squashed and especially heated over time. There are also nubbles on the facings which will wear in shortly. You can raise the bite point by viciously slipping the clutch fo a couple of minutes, at the expense of half your clutch life!
|Not likely related, but I once grabbed a 1500 Spitfire slave pushrod from my spares while doing a clutch r/r in my 1500 midget. as the Spitfire one is approx. 3/4" shorter, I got the symptoms you describe. Engine/gearbox back out to rectify. Ouch. I must say I don't recall the new clutch having a (radically) different bite point, that is after putting the correct slave pushrod in.|
I had trouble getting the clutch to clear, all new cylinders and several bleeds etc. I found the trouble was the pedal bush worn and the pivot bolt had worked loose and worn an oval hole in the bracket. New bolt,pedal bushes and a rewelded bracket,result perfect clutch and a firmer brake pedal too.
|P J Vass|
This thread was discussed between 23/07/2012 and 25/07/2012
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.