Replacing wheel cylinders

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simmitc
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Re: Replacing wheel cylinders

Post by simmitc »

Well done. I did caution about the pipes and unions seizing, sorry to hear that it happened. The consolation is that the hoses clearly heeded replacing.

When reassembling, you might want to use a small amount of copperease/copperslip as a lubricant on the metal parts, but ensure that it does not go into the system. Using it usually makes future disassembly much easier.
James k
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Re: Replacing wheel cylinders

Post by James k »

You're right about the hoses and I did take that as some consolation when the pipes snapped. I had wire brushed them and soaked in plus gas but they still snapped.

The pipes snapped very easily and seemed brittle rather than twisting and bending first. I'm guessing it's probably a good thing that they're being replaced too.

Are you saying that copperslip is okay to use on the unions themselves as long as it doesn't get into the system?

Thanks
simmitc
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Re: Replacing wheel cylinders

Post by simmitc »

Yes, fine on the threads and also on the interface between the union and the pipe, just not where the fluid goes.
James k
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Re: Replacing wheel cylinders

Post by James k »

Hi,

The brake pipes have arrived so I'm going to start the job today. The next problem I have is that I can't work out how to get the rubber grommets (where the pipe passes through the tie plate) to fit over the pipe. I think perhaps they need to be fitted before the unions but since I have pre-made pipes, that's not an option for me.

Unless I'm missing a trick on getting the grommets on, I'm thinking of just leaving them off and wrapping some electrical tape round the pipes instead.
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Re: Replacing wheel cylinders

Post by panky »

I just put a cut in the grommet to get it on the pipe
Image
simmitc
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Re: Replacing wheel cylinders

Post by simmitc »

might be easier to remove them from the car, push them over the pipe, and then refit to the car after passing the pipe through the hole. Another option would be as above, but cut a slit in one side of the grommet so that it is easier to refit - it should open back out to form a 360 degree cushion. Good grommets should be soft enough to fit easily, but they can harden with age, so perhaps you need new ones of those too. They can be purchased with varying ID for a given OD.
James k
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Re: Replacing wheel cylinders

Post by James k »

Thanks, I made a cut in the grommets as suggested and they seem to fit securely.

I've just finished replacing the two front brake pipes and flexi hoses. It's all gone together fine, my only question is how much solid brake pipe is acceptable below the flexi hose? One side has ended up the same as before but the other extends further down.
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Re: Replacing wheel cylinders

Post by panky »

Mine is the same

Image

Image

I bent it up slightly to get it tucked up as high as possible
Image
James k
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Re: Replacing wheel cylinders

Post by James k »

I've done the same as you now and bent the pipe up slightly. I got one side assembled with new cylinders and bridge pipe. The bridge pipe was the correct length to route it along the backplate like the old one. I've been delayed again though by an error I've made multiple times before, ordering the wrong number of screws! I thought "two per side, both sides" and ended up ordering two instead of four!

I've ordered more so hopefully they'll be here tomorrow and I can finally finish the job.
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Re: Replacing wheel cylinders

Post by James k »

I've got it all together now. New cylinders, shoes, front pipes, bridge pipes, flexi hoses, screws and copper washers.

It was all pretty straightforward and only took a few hours of actual work. Most of my time was spent ordering parts and waiting for them to arrive!

I've bled the front brakes using the standard "up, down" method with my wife on the brake pedal. I'm still not getting a nice hard brake pedal though. I've read some things here about leaving it to sit overnight so I'm hoping it might have improved when I come back to it tomorrow. Otherwise, any suggestions would be much appreciated.

Thanks again for all the tips!

James
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Re: Replacing wheel cylinders

Post by mowogg »

Bleed the back brakes. I always find some air gets into the rears somehow.
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Re: Replacing wheel cylinders

Post by James k »

Thanks, I'll do that tomorrow. Do you manage to bleed them with the wheels on or jack it up and remove them? The access seems pretty poor.
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Re: Replacing wheel cylinders

Post by mowogg »

I have done it without taking wheels off but I would as use against it. Much easier to take the wheel off and get clear access
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Re: Replacing wheel cylinders

Post by James k »

Okay, I think it's all done now, fingers crossed!

I bled the rear brakes and a lot of air bubbles came out. I've just driven the car and it brakes in a straight line and has a firm pedal.

I inspected all the unions for leaks after driving and I can't find any so hopefully that's all done for now.

The only problem I have now is that I've blown the fuse to the horn by accidentally shorting it with a spanner while changing the brake pipe!
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Re: Replacing wheel cylinders

Post by mowogg »

Well done.


You should benefit now from thr reliability of you new components
James k
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Re: Replacing wheel cylinders

Post by James k »

I hope so. All the cylinders I took out were pattern ones with the o ring seals. I've replaced them with 'genuine' and lubricated the pistons with red grease. Hopefully this means they'll be more reliable than before.

Do you know what the purpose of the rubber o ring on the outside of the cylinder is? I can't figure out what it's supposed to do wince it doesn't actually make contact with any moving parts and just sits on the casting.
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Re: Replacing wheel cylinders

Post by Myrtles Man »

It's a dust cover.
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Re: Replacing wheel cylinders

Post by kiwimog »

Just joining this thread as I think my question fits logically here...

After sitting for too long my brakes needed some work. Sure enough, inspection revealed at least 3 of the wheel cylinders sticking/stuck so I've overhauled, red rubber greased and bled the system.
If continually pumped the pedal is firm, but if I give it a couple of minutes the first pedal pump goes to the floor and requires 2nd pump to firm up.

Is this air still in the system or symptom of master cylinder problem??
mowogg
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Re: Replacing wheel cylinders

Post by mowogg »

Most likely to be air still in the system.
myminor1969
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Re: Replacing wheel cylinders

Post by myminor1969 »

I've had this scenario several times on Minor brakes.
Could be the master cylinder.
Check and make sure all connections are dry and no leaks.

The only way I found to get the air out was:
Fill master cylinder to normal level and replace cap.
Get an assistant to pump the pedal several times until firm and hold with as much force as possible.
Undo bleed nipple and drain into jar checking for bubbles.
Once the pedal is down to the floor (do not pump) lock the bleed nipple off.
Repeat on all nipples starting from the furthest first.

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