Technical Rear brakes

[Jockcl500]

During the lockdown I have been passing the time doing maintenance jobs.
I noticed a slight weep under the dust covers on both the rear wheel cylinders, so ordered 2 from ECP expecting to wait a week, they arrived next day - great service.
Getting at the bolts holding them needs an open ended spanner, they are 3/8 and not metric as you would expect, plus the brake pipe was rusty and even gently trying to slacken, it snapped, so had to make a new brake pipe to fit, which I wasn't expecting, but all went well although it must be about 11 years since I have had to make one.
I didn't change the shoes, just lube the mechanism and grind the lip off the drums, they will do for a while yet.
The wheels were very rusty, so while they were off, I decided the clean the rust off and paint with rust treatment, then a coat of black paint.

 

[varesecrazy]

Which part had a 9.5mm hex?

The securing bolts for the cylinder..
Or the nut:ferrule on the brake line?

 

[Jockcl500]

Which part had a 9.5mm hex?

The securing bolts for the cylinder..
Or the nut:ferrule on the brake line?

The cylinder retaining bolts are 3/8
Do you have metric spanners in 0.5mm increments?

 

[Pugglt Auld Jock]

I noticed a slight weep under the dust covers on both the rear wheel cylinders
Getting at the bolts holding them needs an open ended spanner, they are 3/8 and not metric as you would expect, plus the brake pipe was rusty and even gently trying to slacken, it snapped, so had to make a new brake pipe to fit, which I wasn't expecting, but all went well although it must be about 11 years since I have had to make one.
I didn't change the shoes, just lube the mechanism and grind the lip off the drums, they will do for a while yet.
The wheels were very rusty, so while they were off, I decided the clean the rust off and paint with rust treatment, then a coat of black paint.

Your post here interests me very much, thank you. Sounds like a virtual carbon copy of what I have observed, and am expecting to have to deal with, on Becky (our 2012 Panda 1.2 Dynamic Eco).

I may have missed it but can you tell me more about your car? for instance what model is it? what year? how many miles on it? etc.

Finally can I send all best wishes from one Jock to another? Are you based in Scotland or having to "suffer" in a foreign land?

 

[varesecrazy]

'Half sizes..' - Some


Its a world wide forum for Italian cars..
So I just stated the hex size in metric

Interesting prospect though.. I will have to measure some..
Pugglt Auld Jock has got this job on his radar

I personally suspect its just 'tolerancing'

 

[Jockcl500]

Your post here interests me very much, thank you. Sounds like a virtual carbon copy of what I have observed, and am expecting to have to deal with, on Becky (our 2012 Panda 1.2 Dynamic Eco).

I may have missed it but can you tell me more about your car? for instance what model is it? what year? how many miles on it? etc.

Finally can I send all best wishes from one Jock to another? Are you based in Scotland or having to "suffer" in a foreign land?

Mine is a 2010 1.2 eco Dynamic with 111,000 on the clock, it was a one owner, supplied and full service history from Arnold clark in Broxburn.
I bought it from a dealer in County Durham, near where I live, it is tidy enough, although I have spent time removing rust and covering it with rust treatment, but I bought it as a cheap run about, but I will keep it at £30 per year road tax, it lets me put my other car off road, for the winter, which costs £570 per year road tax.

 

[varesecrazy]

Who'd have thought
'Central Locking' +500 would add so much to the VED..

Our 2004 active didnt need any hydraulics in the 15 years we owned it..

But I do recall rounding some brake fittings ('propertioning valve') on an Uno..

Had to dismount the entire assembly.. then

file hex's back onto it for 'next time'

Oh the joys of used..

 

[koalar]

I have just written in an other thread

I find it easier to take the hubs and back plate off. There's one bolt at the back that only a thin open ended spanner will fit. Its not worth rounding off. With all the pain that entails. Take your time disconnecting the hydraulics. Its easy to twist the ends off. I always use heat once they start to move lubricate. Then undo a bit, tighten back up, undo a bit more and so on. Of cause it may not be needed but the last 10 or so joints I have undone have needed heat. Plastic coating burns of so needs covering in grease on reassembly

 

[koalar]

Who'd have thought
'Central Locking' +500 would add so much to the VED..

Our 2004 active didnt need any hydraulics in the 15 years we owned it..

But I do recall rounding some brake fittings ('propertioning valve') on an Uno..

Had to dismount the entire assembly.. then

file hex's back onto it for 'next time'

Oh the joys of used..

had to replace the wheel cylinders on both of mine. Weeping cylinders on both, plus one fail MOT because it was sticking

 

[Jockcl500]

Who'd have thought
'Central Locking' +500 would add so much to the VED..

Our 2004 active didnt need any hydraulics in the 15 years we owned it..

But I do recall rounding some brake fittings ('propertioning valve') on an Uno..

Had to dismount the entire assembly.. then

file hex's back onto it for 'next time'

Oh the joys of used..

I do love the Mercedes V8 5.5 litres of joy.
I would never reuse nuts or bolts in that condition, better just replacing with new ones.

 

[Jockcl500]

I have just written in an other thread

I find it easier to take the hubs and back plate off. There's one bolt at the back that only a thin open ended spanner will fit. Its not worth rounding off. With all the pain that entails. Take your time disconnecting the hydraulics. Its easy to twist the ends off. I always use heat once they start to move lubricate. Then undo a bit, tighten back up, undo a bit more and so on. Of cause it may not be needed but the last 10 or so joints I have undone have needed heat. Plastic coating burns of so needs covering in grease on reassembly

I would not even consider removing the hub and backplate to change a wheel cylinder, the bolts are good quality and you will not round them off if using the correct size open end spanner.
I agree lube to aid removal, but if heat is needed to remove a brake pipe, then the pipe and fittings want to be replaced for new.
For the small cost, I wouldn't waste my time refitting parts or bolts that are knackered, prolonging the inevitable and giving you the same **** job to do again, I used to hate following someone like that when I was a mechanic.

 

[DaveMcT]

I've been using the lockdown to sort my 100HP back brakes.

At the back, the upshot is don't bother. You need special pliers to extract a circlip way down inside the hydraulic cylinder. Even with the supposedly correct pliers I got nowhere.

I did find the ABS sensor on RHS was clogged with grease. The wheel bearings were replaced last year so who knows. The bearing is running smoothly. The sensor is now cleaned up. I also cleaned and red greased the caliper sliding pins.

I also noticed a brake fluid weep on one of the caliper connections. I have banjo fittings. That was sorted with a Dowty seal washer. The weep was so slight the (recent) MOT had missed it so had the caliper not been removed, it would have never been spotted.

For winding back the pistons, I used a C spanner on the piston top cross and a trigger clap to push the piston in. Easy to do and cost 2p. Both sides have normal threads on the hand brake wear compensator.

 

[koalar]

90% sure bolts are 10mm and just rust down so a 3/8" fit better ? only .2mm per side.

 

[Jockcl500]

90% sure bolts are 10mm and just rust down so a 3/8" fit better ? only .2mm per side.

I'm sure they are not 10mm
I am slightly OCD and always clean all the bolts on my bench grinder before replacing, they cleaned up like new and are 3/8

 

[chris3234]

I'm sure they are not 10mm
I am slightly OCD and always clean all the bolts on my bench grinder before replacing, they cleaned up like new and are 3/8

Is be very surprised if any post 2000 car used anything imperial
It would probably be the only imperial fitting on the car?

 

[Jockcl500]

Is be very surprised if any post 2000 car used anything imperial
It would probably be the only imperial fitting on the car?

Yes I thought it was an odd size too, but it is probably the same bolts they have been using on the Panda, since the 80s when I started mechanics.

 

[DaveMcT]

Unless there is no access for an allen key, replace with M6 socket head high tensile zinc plated NOT stainless. Use a good quality copper grease to keep corrosion at bay. A plastic cap in the socket is also a good idea, but you could fill the socket with grease.

These would do the job -
https://www.ebay.co.uk/itm/M3-M4-M5...hash=item3f73332042:m:mHWL5LItYhNjkMrsTvUrXCg

 

[Jockcl500]

Unless there is no access for an allen key, replace with M6 socket head high tensile zinc plated NOT stainless. Use a good quality copper grease to keep corrosion at bay. A plastic cap in the socket is also a good idea, but you could fill the socket with grease.

These would do the job -
https://www.ebay.co.uk/itm/M3-M4-M5-M6-ZINC-PLATED-High-Tensile-12-9-Cap-Head-Allen-Bolts-Socket-Screws/272515670082?var=571589025966&hash=item3f73332042:m:mHWL5LItYhNjkMrsTvUrXCg

I always clean all the bolts, before covering with copper grease, then refitting them. If I have taken it off, it will come off next time easily.
Copper grease on the back plate before fitting the wheel cylinder too.

 

[Jockcl500]

Unless there is no access for an allen key, replace with M6 socket head high tensile zinc plated NOT stainless. Use a good quality copper grease to keep corrosion at bay. A plastic cap in the socket is also a good idea, but you could fill the socket with grease.

These would do the job -
https://www.ebay.co.uk/itm/M3-M4-M5-M6-ZINC-PLATED-High-Tensile-12-9-Cap-Head-Allen-Bolts-Socket-Screws/272515670082?var=571589025966&hash=item3f73332042:m:mHWL5LItYhNjkMrsTvUrXCg

They look like a good alternative.

 

[Pugglt Auld Jock]

I would not even consider removing the hub and backplate to change a wheel cylinder, the bolts are good quality and you will not round them off if using the correct size open end spanner.
I agree lube to aid removal, but if heat is needed to remove a brake pipe, then the pipe and fittings want to be replaced for new.
For the small cost, I wouldn't waste my time refitting parts or bolts that are knackered, prolonging the inevitable and giving you the same **** job to do again, I used to hate following someone like that when I was a mechanic.

I have to say I'm with you on this Jock. I might remove the hub to make fitting the shoes easier but don't think any advantage would be gained if just doing a cylinder - As you can see in this picture of Becky's rear brake, although I haven't tried it yet, it looks like the cylinder can be removed without having to disturb anything else:



(I suppose also there's always the slight chance of the inner bearing hanging up on the stub axle and getting damaged, although that's probably a small risk) I would be reluctant to risk breaking the back plate retaining screws - which I think are Allen Hex Screws? - I'd rather mechanically attack the wee bolt holding the cylinder even if it had to be destroyed to remove it.

I've read before on here about using a blow torch on the brake pipe tube nut and how it melts the coating on the pipe. I'd rather just cut the pipe off the nut so I can get a socket or 6 point ring key on it and make a new pipe up. (I have great hopes for my new Vibro Sockets on jobs like this). This shot of the back of Becky's back plate shows how it will easily come out with the cylinder if you were to cut the pipe off:



Of course then you've also got to get the tube nut out of the flex hose at the other end. I wouldn't ever put a flame anywhere near a flex hose fitting. New vs old nuts/bolts/setscrews on a job like this? For the negligible expense I'd always just use new ones. As I said above, if you are going to make a new pipe then just cut the old pipe off at the tube nut and forget about undoing the tube nut at all, it'll just come out with the old cylinder. In fact even if you are not replacing the cylinder - maybe just doing the pipe - if you cut off the old pipe and remove the cylinder complete with the tube nut still in it, you can then grip the tube nut in your workshop vice and unscrew the cylinder from it thus saving the cylinder for reuse. I've often found a stubborn tube nut which I can't shift with the cylinder still fitted to the backplate is relatively easily removed in this way. Even at the flex hose end cutting the tube off means you can then get a single hex socket on it which makes removal much easier.