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MG Midget and Sprite Technical - Salvageable 1500 master cylinder?

Newbie, be gentle...

Decided to have a go at overhauling the master cylinder due to a jamming front caliper.

Have I wasted a day in my life fighting circlips stripping this?

Any advice greatly appreciated.


J Dunn

Its possiable... the piston in the front caliber is mild steel and can rust in place and not moving freely and jambs into place agianst the brake rotor

Beyound that I Cant offer any additional info

Can you eloberate more on your cars specs and the issue your facing
Prop and the Blackhole Midget

Complete replacement M/cs are not expensive these days and I would always change the whole thing rather than mess around with replacement seals etc.
But why would overhauling the cylinder fix one sticking caliper?
I would buy two new calipers and a new M/C (and probably two new rear wheel cylinders at the same time)and do a proper job.Assuming the pipework is in excellent shape.
You are talking about a braking system without a dual circuit, after all.
JB Anderson

that pic looks like the late tandem m/c to me so it is dual circuit...
David Smith

J Dunn: Mmmmm - I think I would have had a look at the calliper first too! Now you have the master cyl in bits it could well be becoming expensive. Unless you are really confident, replacing the seals in the master cyl can be prone to problems so as suggested you may need to replace it too. Welcome to the world of "can of worms" spridget maintenance! The decision is where you draw the line on replacements. If the rest of the braking system seems ok, your rear cyls should be ok. If the later cars have similar mountings for the rear cyls as the 1275, there is an equally traumatic circlip to tackle at that end!


You could try http://www.powertrackbrakes.co.uk
People have posted previously about good quality components from there!
G Williams (Graeme)

Nothing wrong with overhauling a master cylinder. Having said that, the late 1500 dual-circuit m/c is a PITA to rebuild.

One cause of sticking front caliper is a collapsed flexible hose. Something else to check.
Dave O'Neill2

Hi J D, I rebuilt my 1500 DC MC, Dave is right, PITA. Yours looks broken, I think the linkage between the pistons is knackered, buy a new one and follow JB's advice, change everything, if you can afford it think about alloy calipers. PS I had to make a special pair of Miniature Circlip pliers out of some cheap 4" pointy nose electronics pliers by grinding the jaws into a circular shape, I can send a pic later today say 3-00am your time if you decide to continue with the rebuild.
Cheers
Rod
R W Bowers

Thanks for the replies, was a PITA to dismantle, until I fabricated a tool to get the deep circlip out.

RWB, yeah, not many pics on google of the innards, but something catastrophic has gone on inside.

I replaced the offending caliper first of all, but that jammed on too. So following the brake pipe back to the cylinder looking OK, reckoned the MC was the problem.

Ordered a new one last night!
J Dunn

Similarly, I had to modify an old pair of pliers. As well as grinding the ends in order to grip the circlip, I had to grind the outside of one side in order to fit into the bore of the cylinder and the inside of the other side to clear the pushrod.


Dave O'Neill2

You replaced the bad caliper...but did you also replace the hose from the caliper to the pipe also

The hose can look great on the outside but be collapsed and non funtioning on the inside

I feel your pain, ive rebuilt mine twice, third time it was replaced with a duel master cly from tilton and ive never regretted

Btw... you want to make sure the newrebuild kit is from (ray something) the other kits are natral rubber and note very compatable with dot 3/4 fluid...the (ray ???) Is made from petrolium based rubber and is very compatable with modern day brake fluids

Good luck

Prop
Prop and the Blackhole Midget

Raybestos.... thats the manufacture im thinking of...these are the only ones I know of made from petroleum based rubber not natural rubber

Prop
Prop and the Blackhole Midget

J D, make sure that the small nylon?? control valves are fitted correctly in the front and rear pipe unions on the MC, from memory, they control the flow of fluid back into the MC and prevent excessive suction pulling air into the Wheel cyl's and the calipers.
Prop is correct, order new braided stainless hoses if the budget will run to them. HTH
Cheers
Rod
R W Bowers

be very careful when buying anything new with rubber in it as a lot of rubber is now absolute rubbish and s/s or other braiding can hide how quickly it can deteriorate which can be only months or weeks in some cases

I think the Goodridge s/s braided hose kits are still well made (not heard otherwise) and perhaps an alternative here, steel braided Teflon hose - http://www.venhill.co.uk/Hoses_&_Cables_-_Car/MG/MG-002_MG_midget_MK2_to_MK5_BRAKE_3_LINES.html
Nigel Atkins

Replaced hoses with Goodridge a couple of years ago, so discounted those as a cause early on.

Will fit the new MC in the next couple of days, will update on whether jamming problem has been fixed.
J Dunn

If it dosnt fix it... next stop the proportion ing valve that moss sells for $600

Yeah... I thought that was funny also

Prop
Prop and the Blackhole Midget

This thread was discussed between 30/06/2013 and 02/07/2013

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