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MG Midget and Sprite General - Brakes and springs (random questions!)

Evening all, hope you are all well.

I was pottering about in the garage tonight (as I'm sure a lot of you do) and I have ended up with a couple of obscure questions.

1. Is there an easy way to get the pistons out of a brake caliper when they are disconnected from the car?

2. What is the height of a standard 1500 spring? I measured 10 1/4 inches. What was the difference between these and the 1275 springs (I assume stiffer due to heavier engine, but were they also longer?)?

Thanks for satisfying my inquisitive mind!

Cheers,
Malcolm
M Le Chevalier

Malcolm.
Easiest is with an air line onto the hose connection. Or rig up a grease gun to pump pressure in. You may need to jiggle around with clamps so that both pistons come out, rather than one move and the other not.

Actually re-conditioned callipers are a pretty good option price wise, especially if your pistons are pitted and need replacing too.
Guy

And yes to your other question!

Oh how it would be nice to have a garage ...!
rachmacb

if you use an airline - keep your fingers clear and use a rag etc to cushion the exit of the piston .. they can stick and then go with a pop and some speed !

Grease gun with oil or grease probably safer.....but messier.
Dean Smith ('73 RWA)

Guy, I must be missing something... calipers are like £50 each! No? Much cheaper to pull them apart and clean them up with new seals?

No air line or grease gun, damn! When I said easy I was hoping there would be a secret button or a magic word you could shout at them to make them pop out! ha ha.

Random question number three what does the 'plug' number 16 do? Anything or nothing?

http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=1216

Cheers,
Malcolm
M Le Chevalier

I said reconditioned but actually meant to say new ones! At around £54 they are a pretty good buy as compared to buying parts and spending ages cleaning up and repainting old callipers.

Sorry, cross posting again!

When I came to do mine I needed new pistons as well. I think the parts came to around £36 and I know that getting the seals in without distorting the dust ring can be a real pain. I opted for the new ones at a little bit more but they are nicely finished and don't require painting (Or can be painted onto nice clean metal rather than spending hours on the old ones)

Guy

I also use the compressor to push them out, but I've also had a fair bit of luck levering them out with a couple of screwdrivers or getting a large set of vise grips around them. Both methods work but if you are going to reuse the pistons you need to be very careful and protect the smooth finish. The last set that I done were on the TR4 and they had not moved in thirty years.I had to weld some angle iron to the pistons to use as a lever to break them out. I now always fit the stainless steel pistons if possible!

Paul
Paul Barnes

thanks for the tip on the stainless pistons paul. Didn't realise they existed, but a quick search shows they are only a couple of quid more than standard so a good upgrade if required.

Malcolm
M Le Chevalier

spring length - I remembered seeing this in the Haynes - it shows free length 9.85" (250 mm)

however - I also remember reading in Terry Horler's book that the spring for the 1500 was increased to 10.2" (259 mm) - page 133 - http://www.amazon.co.uk/dp/1906133336/ref=pe_28611_26372931_pe_vfe_dt1

which coincides with your measurement and my dislike of the Haynes for accuratecy

for the (later) 1275 Haynes has 9.59" (244 mm) whereas Terry Horler's book on the same page has 9.85" (250.2 mm)

the plug I can only guess is to keep muck out
Nigel At

I have wondered about that plug (#16). Probably there is a hole that had to be machined from the outside, to connect two areas in the casting, and that plug is to close off the end, after drilling.

There are several plugs like it on the engine, where oil ways were drilled after casting, so that's what I suspect this one is on the caliper.



Norm
Norm Kerr

another vote for SS pistons. I got mine from minispares, as they're the same size as the mini 8.4 inch brake calipers. A front hub bearing outer part from a mini pushes the swiney dust seal retainers in fantastically well with no bending or mashing of the thing...
Rob Armstrong

This thread was discussed between 31/08/2011 and 01/09/2011

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