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MG Midget and Sprite Technical - Need to double pump brakes

Morning. I would welcome a steer from the BBS on what might be wrong with my brakes. I have a Mk 2 Sprite (1961) with drums all round. The brake pedal is soft and you need to double pump to get good braking. The brake fluid level is fine. When I put on the handbrake the problem is still there so does that eliminate rear drum brake adjustment as the issue? Will it simply be air in the lines somewhere that is the cause? I'm not that happy driving it until it is sorted. Thanks.

Tim
TJ Prime

Tim, my first step would be to adjust the rear brakes. If there is too much travel in the rear pistons then the whole braking system will be effected - with a knock-on effect on the proper operation of the front brakes. Pulling on the handbrake levers directly onto the shoes, and doesn't take up any maladjustment in the hydraulic pistons.
Guy W

If the pedal is soft it's most likely air in the lines, but the question is, how did it get in? A worn cylinder can draw air in on return. But then you would most likely be losing fluid. I'd suggest adjusting all brakes and bleeding the system. Inspect all cylinders for leaks.

Les
L B Rose

Certainly sounds like air somewhere. When you look at the wheel cylinders peel back the rubber dust cover on each. It should be completely dry inside. Any sign of fluid means the cylinder is on the way out.
Mike Howlett

Im with Guy on this one...start with his advice.

Steven Devine

I do think that they will probably need bleeding as well, if the pedal feels spongy. But adjusting them is the first step as it is difficult to properly bleed brakes when they need a "double stroke" to get any sort of pressure.

If you find that they can be adjusted up tighter, then obviously some wear has taken place on the shoes. And from this it follows that the drums are likely to have retained some of that worn material from the shoes as brake dust. Worth taking the drums off to clean them out and then check the cylinders for signs of leakage as Les and Mike have advised.
Guy W

I agree, even if it eventually needs bleeding, you will still be able to pump them up if it's drums *FRONT AND BACK*, unless you take out the free travel first.

First job, adjust both sets, and take it from there.
Lawrence Slater

When did you last change the brake fluid? Brake fluid, being hygroscopic, tends to absorb water over time which can lead to ineffective brakes, worn seals and rusting cylinders which could lead to the symptoms you describe.

It is recommended to change every couple of years.

Don't ask how I know ........
Peter Blockley

possibly old brake pipes flexing, ie expanding due to old age (like most of us??)
a reid

the 1st thing id do is replace the front drum brakes with calipers and disc... and chuck the drums into the trash
Prop and the Blackhole Midget

Update on the brakes. Adjusted the rear brakes and that was no problem. It seems to have sorted out the issue pretty well. I also tried to bleed the brakes but found that my garage where I had taken it the other week to put it through the MOT had done something to the rear brake bleed screws such that they are pointing upwards and it is impossible to get them open other than with a socket set which is all very well but not if you want to get an ezibleed hose on it too. Question is, do I take it back to the garage to get them to put the brake bleed screw back to where it was ie. accessible for a spanner or live with it being awkward? I'm inclined to do the latter.

TJ Prime

" --- done something to the rear brake bleed screws such that they are pointing upwards -- "

Can you take a picture? I can't think what the garage might have done without seeing it.

Why would the mot station be playing with it anyway?
Lawrence Slater

This thread was discussed between 22/08/2015 and 29/08/2015

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