how to tell if brake cylinder is working?

[guymcc]

Hi,

sorry for the really novice question but how can you tell if the rear brake cylinder is working, ie how do you function the brakes? I'm thinking it's a two man job, ie one in the car with it started and the other watching the back brake cylinder/shoes doing their bit.

I have the n/s/r drum off, which needed a fair bit of hammering by the way, and now i'm looking at the cylinder and shoes. I really am not sure whether or not you can tell just by looking at it to know if things are working. I'm on my own at the mo. so no one to give me a hand.

Does the cylinder push out both the top shoes as well as the bottom, or does it just push out one?

I will go and take a photo and post this up, picture paints a thousand words and all that!
Oh the reason i've opened up the back brakes is to get it fit for an MOT, it failed last year with various points, mosly brake related
ie... nearside rear brake recording little or no effort
... nearside rear brake binding..

any pointers in the right direction would be greatly received, trying to get things done before the rain comes on friday!!

[guymcc]

ok here's a close up[frame][/frame]

hTh

[DaisyMayFozz]

well im not sure, probably you will need to get someone to press the pedal in the car and see if anything moves or mark where the shoes are with a piece of chalk and then rig up a weight( brick?) on the pedal so that it is pushed down and see if anything has changed. Those shoes don't look too bad, Could the brakes not have been adjusted properly?

Hope that helps
Chris

[Budgie]

well you could try placing some masking tape around the shoes till it just meets the other end,while the shoes are at rest.then apply the brake ,then check to se if the tape has parted bearing in mind the rear shoes have one leading edge i,ve done this myself years ago when i,ve been on my own fiddling

[mike.perry]

Did you release the handbrake, ensure that the handbrake operating lever on the back of the wheel cylinder was fully released and that the brake adjusters were fully slackened off before trying to remove the brake drum?
To check that the rear wheel cylinders are working, support the axle on axle stands and try turning the wheel with someone gently pressing the brake pedal..
To check the fronts remove the drum and get someone to gently press the brake pedal whilst you watch to see that both pistons are moving.
The rear cylinder is in a slot in the backplate so that one brake shoe pushes against the drum and pushes the cylinder in the slot so that the other brake shoe presses against the other side of the drum

[guymcc]

^^thanks for the hints. Does the car need to be running? I'm thinking yes, so that there is pressure in the system.

I didn't think the 'insides' look too bed either. Only found out about loosening off the shoes after I took off the drum! the handbrake is something else that needs adjusted. Am I right in saying this is done at the habd brake itself under the bit of carpet, like you would for a bike brake cable (in rudimentary terms at least)?

As an aside where about is the best place to put a jack stand, I currently have it under the fixing where the leaf springs attach, forward of back wheel.

thanks again! the more DIY you do the more you get in to it!!

[guymcc]

Oh another thing...
there was a third screw on the outside of the drum, but it just seemed to be attached to a sort of dead end nut on the other side of the drum?

took the other two out before removal.

[MarkyB]

Does the car need to be running?

No, it doesn't.

If you can't find an assistant to push the pedal then use your ingenuity to find a way.
How about a bamboo cane balanced between the back plate and the shoe? You should be able to see if that moves.

Is there some reason to think it isn't working like an MOT fail?
Otherwise, if it ain't broke, don't fix it applies.

[mike.perry]

The engine should not be running when adjusting the brakes
To adjust the handbrake support the axle on stands, remove the wheels and adjust the brake shoes. Grease the handbrake cables and the inner cable where it comes out of the outer cable behind the drum. Replace the wheels and apply the handbrake until it just bites then try turning the wheels. There should be equal pressure on each wheel. If one turns easier then tighten the cable on that side. When they are equal then pull the handbrake on until the wheels lock to check that they are both locking equally.
The cross head set screws are hub retaining screws, not tightening screws. Replace the drum and tighten it using two wheel nuts on diagonal studs, then replace the set screws
Do not forget to tighten the wheel nuts with the wheels on the ground before replacing the hub caps

[guymcc]

MarkyB – cheers, Had various notes on the MOT fail, so yeh that’s why I’m having a look.

Offside rear brake drum contaminated by brake fluid, (see photo).
Solution – replace cylinder and clean up shoes and back plate until dry?

Both nearside and offside brake recording little or no effort (effort written on MOT card but I think he means effect?
Solution – adjust shoes?

Both nearside and offside parking brake recording little or no effort
Solution – tied in with adjusting the shoes, and perhaps adjusting the cable?

Nearside rear brake binding
Solution – not too sure why this is but think once cleaned up and adjusted this might cease to occur?

Offside front brake binding
Solution – again not too sure why this is happening? Haven’t opened up the front yet?

Mike.perry – thanks for your reply also

It is all coming together kind of!

Will get another chance to work on the car Thursday. Fingers crossed the rain stays off!

[guymcc]

here's the photo of the offside rear, contaminated on the inside![frame][/frame]

[MarkyB]

It will either be contaminated with oil from the axle, or brake fluid from the axle.
Oil will smell quite nasty.
None of it is expensive or difficult to sort out.
Go for new shoes and cylinders, a paper gasket and a rubber O ring seal.
The cylinder looks like it is stuck open to me, unless you are completely skint, replace both of them.

[guymcc]

Where is the paper gasket and rubber o ring seal? and what are they for? Why would I need these items?

Do the shoes and cylinders come as sets for both sides? Don't want to shell out for things that actually might be fine.

[beero]

I have listed your faults and my suggested solutions.
You can buy cylinders separately, shoes come as an axle set (ie four)
Brakes are the one thing you must not get wrong or save money on!

Offside rear brake drum contaminated by brake fluid.
Solution – replace cylinder and REPLACE shoes, clean drum and back plate with brake cleaner

Both nearside and offside brake recording little or no effort
Solution – Check the cylinders to see that the pistons are free to push out and return with the spring pressure

Both nearside and offside parking brake recording little or no effort
Solution – could be the fluid on the linings, replace shoes, adjust shoes then adjust handbrake cable

Nearside rear brake binding
Solution – could be adjusted up too much or a seized/partially seized cylinder

Offside front brake binding
Solution – could be adjusted up too much or a seized/partially seized cylinder(s)

[bmcecosse]

As above - both rear cylinders appear to be stuck open - or the handbrake cables have been adjusted up too far - but the MOT comments confirm the brakes are seized. The wet shoes are scarp - so you need two new cylinders and a set of new shoes. Slacken off the handbrake cables at the lever inside the car before you start the work - and make sure the cables are not broken or seized. If in doubt - fit new cables. Once the new parts are in place (and all oil/mess removed and the drums thoroughly degreased) fit the new shoes and the drums - and adjust up the shoes till they are just rubbing very slightly. Only then start to tighten up the handbrake cables until the lever clicks up 3 or 4 notches until the drums become (evenly) impossible to turn. Then turn your attentions to the front brakes ! It's likely some of the front cylinders will need renewing too - possibly best to just renew them ALL - and fit new shoes there too. When all fitted - it will be necessary to bleed the brakes through. Start at the rear nearside then off side - then front nearside and finally front offside. It' s a busy day's work........provided you have all the parts to hand. It's also highly likely you will find you need some new brake pipes and very possibly new flexi pipes too......

[guymcc]

Thanks guys.

I'll get on with ordering the parts! Looking forward to getting stuck in and getting this all sorted!
Great to get a way ahead with these things, they can drag on otherwise!

[mike.perry]

Don't forget to top up the brake master cylinder.