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MG Midget and Sprite Technical - Clutch slave cylinder replacement

Hi

Any tips please for removing and replacing the clutch master cylinder please? I have looked in the Haynes Manual and factory Workshop Manual but just a very bald description of removing two bolts, and clevis pin and split pin and careful not to dribble fluid everywhere.

How do I get to the top bolt? Best way to jack the car up (nose high at the moment, do I want it jacked up on one side front and back?). How do I get the clevis pin and its split pin out - access seems an issue?

I have a new 7/8" AP Caparao slave cylinder to go in, plus modified the top mount on it to make later removal easier (slotted the hole in the casting). I have a remote bleed to fit. Thanks to Alan A for such sage advice for both - we do listen you know!

While under the car today saw the PO had decided that the two lowest gearbox set screws that bolt to the engine plate were not needed!

Car is 948cc MkII Sprite with a smooth case gearbox. Should be a 7/8" slave cylinder and who knows what pushrod is in there - I am not sure what I will find. Think I should have bought a new clevis pin.

Cheers
Mike
M Wood

I normally use a cranked ring spanner for the top bolt. If you're really lucky, it'll loosen off after a couple of turns and you can unscrew it by hand.

Access to the clevis pin is not normally an issue.
Dave O'Neill 2

Mike, thread title says slave but your first sentence says master - which one are you struggling with?
David Smith

David

Sorry, looking for info on slave cylinder replacement.

Best wishes
Mike
M Wood

Mike,
don't you have the access hole in the footwell to get at the top bolt, having cut the top off the top bolt hole on the slave so that you can locate the bolt and washer loosely and slide the slave up to the bolt and washer (and have the washer jam at the wrong end, try again) then fit bottom bolt and washer.

Alan put a photo up recently of the chopped slave but I can't find it.

The clevis pin if not too worn might be better than modern ones if the modern ones are now too soft(?).

Look on the bright side Mike perhaps those two lowest setscrews vibrated out. :)

Nigel Atkins

I also use a cranked ring spanner on the upper bolt, as Dave O said. If you have a spare gearbox casing handy, you can dummy fit an old slave and then mark the inner protruding section of the bolts and cut them down so they are just the right length, this makes screwing them back in a lot easier and quicker. Another useful mod is to use an R clip instead of a split pin to lock the clevis pin.
David Smith

Mike
I feel your pain - having been there with a frogeye. Assuming its the same set up on your Mk2, the slave is held on by two bolts, one accessed from under the car,the other is through the “window” at bottom of driver's footwell.
I removed steering wheel for easier access to footwell
The bolt is 9/16 inch and I found a ring spanner was best.
Replacing the slave is very much easier. I cut a slot in the slave's top bolt hole, so the bolt can be fitted first (easy access when slave not in situ) and then slave can be slipped into the bolt, and bolt just finally nipped up from foot well. The second bolt is easy.

By the way, remember the bleed aperture is the one on top (manufacturers often put bleed valve in the end aperture so it fits in the box).
As bleeding through the foot well looked a nightmare, I installed a remote bleed point. Made it very easy.
Graham V

Thanks all, great info.

Got the old slave cylinder off and put a new genuine 7/8" one (AP Caparo/920E) back on, having modified the upper bolt hole to a slot and fitted a remote bleed.

Problem now is that the replacement clutch slave pushrod I purchased (part number 13H21) is a shorter than the old one (overall 2.75 inch compared to 3 3/8"), see picture noting the oval hole in the old pushrod.

What is the correct pushrod length for a 948cc car with 7/8" diameter slave cylinder please? I note I am delving into the unknown so not sure what the PO has done, state of the clutch yoke or the state or spec of the clutch (the car did move and engage gear OK before the slave went). What are the alternative pushrod lengths available for the 1098 and 1275 Spridgets as well as Minis etc?

I note the 13H21 clutch slave pushrod is shared with some MGAs: http://mgaguru.com/mgtech/clutch/ct_108.htm

I have seen a clutch slave pushrod for Minis on the Minispares website, part number 13H396, but length not stated (but have seen it mentioned elsewhere as 'about 90mm' which looks might be what I have removed): https://www.minispares.com/product/Classic/Clutch/Fittings/13H396.aspx?0601&ReturnUrl=/product/Classic/Clutch/Fittings/22A2204FK.aspxBack%20to

Cheers
Mike



M Wood

Hi

On further trawling of the archives, I may have my answer on 948 engined car clutch slave cylinder pushrod lengths:
http://www.mg-cars.info/mg-midget-sprite-technical-bbs/slave-push-rod-1275-2014050820003715357.htm

https://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&mode=archiveth&archiveyear=97_2014.dat&access=&subject=97&subjectar=97&source=T&thread=201408041919436235

Once again the BBS has the answer!

Cheers
Mike
M Wood

This thread was discussed between 01/07/2020 and 12/07/2020

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