Replacing NS Rear Wheel Cylinder

Post by **xpress** » Mon Jul 27, 2009 8:32 pm

Forgive me for asking this but what and where is the spring? are you referring to the leaf spring? Is it ok to jack up on this long curved metal beam/leaf spring at the rear, close to the wheel? I have jacked up modern cars but they have jacking points and their own jack and I am a little more cautious with an older car!

I just went to a local big diy store and i got some 3mm and 5mm clear tubing 1 metre each for bleeding the brake fluid, how long roughly do you guys cut down the tubing to? I just have to get some dot 4 brake fluid tomorrow.

My trolley jack is very old and leaking so I am going to throw it away and get a new Clarke one. I have a scissor style peugeot jack with a flat top to it with a notch in the middle, trouble is with using this, I am not sure how far under the car I can get, I am going to jack up behind the wheel on the axle tube, or a suspension component.

Post by **bmcecosse** » Mon Jul 27, 2009 11:12 pm

Jack under the rear spring (yes - it's the curved steel thing!) centre pan - where there will be 4 U bolt studs sticking down. Don't go under the car unless it is SECURELY supported - the Peugeot jack sounds horrible - don't rely on it for anything! Your old trolley can probably be repaired quite cheaply - just check your local Yellow Pages. MACRO and others often have good deals on trolley jacks - with 'free' axle stands thrown in.

Post by **xpress** » Tue Aug 11, 2009 10:28 pm

Hi fellas, today I jacked up the car and had a look around, as you can see I have been a good boy using an axle stand. The cylinder hasn't been leaking, there was no sign of brake fluid on the shoes and linings. there are traces of axle oil on the middle of the drum and on the middle plate, that's about it.

I have a couple of questions, here's a picture of the wheel cylinder, do I have to back off this bolt in the yellow circle, just the one bolt to remove the brake pipe fitting?

I was expecting two sets of bolts to turn as illustrated in the workshop manual. Is this big bolt the banjo bolt? Any way of taking this pipe out with the banjo bolt attached thus making it easler to re attach? What am I going to see when I slacken this big bolt, is it called the banjo bolt?

Secondly, do I tap out this pin in the red circle by tapping the bottom of it out? Will this release the handbrake cable from the wheel cylinder? I can't see a boot there.

Thirdly do I need to use a lot of plusgas/wd40/releasing agent and pray?

Lastly, do I HAVE to take off the shoes and the springs completely or can I leave them in place?

Cheers!

Post by **Mick_Anik** » Tue Aug 11, 2009 11:51 pm

That brake pipe looks to be in a SHOCKING condition - rusty as hell! DO NOT DRIVE THE CAR! Perhaps give it a go with a stiff wire (hand) brush, and show another picture.
I could be wrong, but I really don't like the look of that pipe! There should not be any 'pitting' of the pipe material ie rusty indentations. When these get very bad, you can press the pedal and blow a hole in the pipe - NO BRAKES!!!!!

I'm sure others will be coming in on this.

Post by **Mick_Anik** » Tue Aug 11, 2009 11:57 pm

And further, the handbrake lever pin in the red circle looks like it hasn't been moved since the car was made!

I think you're going to have a lot of cleaning and servicing to do - but don't worry....it's not difficult.
It looks like it's time to strip things, give them a good clean and a lick of paint, and get it all back together with grease in the right places. Once you've done that, future maintenance is a breeze, if you keep on top of it.

'Neglect rectification' is where you're heading! Possibly lots of it....there's a good chance that the rest of the brake system is in this sad condition. Possibly other areas, too, judging by the crusty look of everything in the picture.

Post by **d_harris** » Wed Aug 12, 2009 1:12 am

I'm with Mick that you need to have a proper examination of that pipe and a good clean up in the area.

To remove the cylinder you need to undo the yellow circled union (brake pipe) and from the red bit you are correct that you need to pull the pin (remove the h/brake cable and replace the pin and splitpin so it doesn't get lost!!) then you need to remove the shoes, springs and adjusters making careful note of the layout. (big screwdriver to lever off) the cylinder should then come out with a bit of wiggling

Post by **bmcecosse** » Wed Aug 12, 2009 7:35 am

And lots of 'praying' as you suggest ! Take a few more pics before you dismantle anything - so you know how it all goes back together. The brake pipe does look a bit poorly - be aware it has 3/8" BSF threads on the nipples at each end if you are having a new pipe made up somewhere - and DO look at the other side while you are in there - it's likely in the same poor condition. MOT should pick up any badly rotted pipes - a bit of surface corrosion is allowed, but not any 'pitting'. Use of Kunifer (NOT copper!) pipe eliminates all corrosion in future!

Post by **d_harris** » Wed Aug 12, 2009 7:47 am

And at around £25 for a set of pipes, well worth it!!

Post by **Mick_Anik** » Wed Aug 12, 2009 11:30 am

The problem with estimating brake pipe corrosion is that there can always be one little 'pit' that is worse than the others. Movement of the pipe as you carry out the work can weaken it still further. Even if it initially holds under pressure, the corrosion process can be speeded up. I have in the past tested the pits by forcefully twisting the point of a sharp nail into them to see whether they "give", and scratching around generally.

As pointed out....better by far to get a set of pipes made up, and instigate a general parts upgrade over time, if cost is an issue. If you have the cash - a new brake system is a wonderful thing. Once installed, it's a pleasure to maintain! Beautiful in its simplicity!

I ruminate on the condition of the master cylinder on a car looking as crusty as this.

And don't forget - the pipes to the brake cylinder move slightly with the cylinder. I always shape my rear pipes to minimise the stress at any one point........a couple of rounded curves in the line. I'm not sure if this helps???? It seems to make sense to minimise any strain at the point of movement, ie at the clip holding the pipe to the axle. Obviously there is no pipe movement on the differential side of this clip.I position this clip a fair distance from the cylinder, also.
This movement increases as the shoe linings wear, if you don't keep the adjusters up. I have read differing opinions on this - one that copper pipes are more prone to problems here than other materials. Regarding Kunifer...I don't know, but am very keen to learn more myself.
Perhaps a separate thread could be started specifically regarding this 'issue', if indeed there is one.
A good modification would be to incorporate a flexible pipe from the axle to the banjo - maybe this is available, or someone knows what to buy to do it.
Because this is so important, I attach two embarrassingly-primitive Windows "Paint" diagrams of my axle brake pipe configuration.

Further input welcome on this area of the brake system!

Post by **xpress** » Wed Aug 12, 2009 1:53 pm

Thanks a lot guys for your input. I am going to take a few more pictures to show you.

Hi Mick, I see what you are saying about the clip, mine is nearer to the diff side of the axle, I will take a pic to show you.

One more thing, so I minimise the stress of this pipe as I undo it, do I have to back off that brake pipe bolt down towards me as you see it in the picture or up and over away from me?

What are your opinions of leaving a car on an axle stand, is it ok to put it on axle stands nearer to the leaf spring on the thinner part of the axle?

And is it ok to leave the car on an axle stand as long as nobody is going to get near it, or should i take it up and down as I am working on it?

Post by **d_harris** » Wed Aug 12, 2009 2:40 pm

The brake pipe unions are threaded in the normal manner (righty tighty, lefty loosey)

In terms of leaving it on stands longer term - imho its better to get it back down on its wheels as you will have better stability - axle stands are 100 times better than a jack but can still topple......

Post by **xpress** » Wed Aug 12, 2009 4:18 pm

Is that my left as facing the wheel cylinder, or left from the perspective from the pipe towards the back of the cylinder? :S

Also, what's the current flavour for underseal at the moment? Do people use hammerite shutz with waxoyl, I was going to use the clear variety of waxoyl after wire brushing and sanding the rust from everywhere! I will take some more pics soon.

Post by **bmcecosse** » Wed Aug 12, 2009 10:40 pm

Your use of the word 'bolt' and your doubts about how to loosen a brake pipe union - rather make me wonder if you should be tackling this job at all! You loosen by turning anti clockwise - looking at the head of any screw or bolt - or indeed this brake pipe union!
Axle stands - if sturdy - will be fine.
"Wire brushing and sanding the rust from everywhere" - hmm - you will have your work cut out! You will need to brush on a 'rust killer' - many brands - most use Phosphoric acid - then a good primer (best with some zinc incorporated) and then a good hard finish paint. Only after all that should you consider any 'underseal'. Many prefer to have simple paint finish below - and frequently hose/clean it! Waxoyl is best injected into closed cavities and box sections - to try to prevent rusting from inside out!

Post by **xpress** » Fri Aug 14, 2009 12:51 pm

I thought they were called the "thingamy" that connects to the "wotsit!" Look like naughty people haven't maintained this moggy. I don't have doubts per se, I am more worried about working with things that have been neglected! I previously used to work on bmws, this is my first classic car!

I just took a look at the master cylinder filler plug, I almost wish I hadn't looked! Not in a good way. Looks like it might be running on the original master cylinder. I think it's not going to be easy to back this plug out. I don't want to use releasing agent and get this undone to do it back up again and have to undo it again. I am thinking of replacing the master cylinder as well now. I can order a filler plug for about a fiver or get a new master cylinder.

What do you think?

Post by **bmcecosse** » Fri Aug 14, 2009 12:56 pm

It should only be on not much more than finger tight. Try it with a socket or good fitting spanner and see what happens! It's a bit of an adventure to renew a master cylinder - so don't do it unless necessary!

Post by **Mick_Anik** » Fri Aug 14, 2009 1:28 pm

I would imagine it's necessary. Every picture we've seen indicates the brake system is suffering from neglect and is due for a total stripdown. Better to get the visual on what's lurking within. It's often possible to refurbish many of the parts even when they have been neglected. We are talking 'life and death' here, so I'm happy to keep going in this thread.

Re the master cylinder filler plug - a hammer and chisel is usually an effective last resort. Not to destroy it, just use the correct angle with the chisel at the edge to get it moving.

What is the condition of the flexible brake hoses? Can you see cracks when you bend them near the metal ends? Have you tried moving other brake unions to see it they move? Have you got the special union spanner - like a ring spanner but with a space in it so you can slip it over the pipe?

Post by **bmcecosse** » Fri Aug 14, 2009 1:58 pm

Aye - but these special spanners splay out very easily. The pics I have seen so far - it's a case of cut the pipe and slip a FULL ring key over the union - and hope it unscrews before the flats round off!

Post by **xpress** » Fri Aug 14, 2009 4:56 pm

Where do I locate the flexible hoses, there aren't any leading up to the rear wheel cylinders!

Can I check with you what socket/spanner to use to undo the filler cap on the master cylinder? is it a 3/4"?

Re the union, I haven't gone back to that yet, I hope that might be ok with some releasing agent/wd40, I have sprayed some releasing agent onto the master cylinder filler cap and left it to soak. today I was just about to get ready to slip a bag over the master cylinder filler cap and then undo the union, then I gulped at the sight of the filler cap, I think where people have put their foot there, the nut has become brittle and crumbled into the carpet!

I am right with you about doing a rebuild of the whole brake system, I am just trying to get this brake system up and running and I will do a gradual stripdown and rebuild. I am tempted to do the master cylinder, pipes to all four wheels and all cylinders tho, in one go so I don't have to refill the brake fluid again for a while, what a job!

i was going to use a 9/16th spanner, I don't have a special union spanner!

That's an idea re the hammer and the chisel, just to get a good bite on the filler plug!

Hi again, I can't see any flexible brake hose, it seems to be metal brake pipes all the way to the rear wheel cylinder!

And thanks all for your support!

Post by **Mick_Anik** » Fri Aug 14, 2009 8:53 pm

There are no flexibles to the rear cylinders - go back to a previous post of mine here regarding this. I think there should be. I raised some other points, too.

I asked about the flexibles, found from the body to the rear axle, in the middle, and on both front brakes, to try to get a better overall picture of the state of the braking system. I'd put money on their being cracked at both ends, every one of them!

If you plan to keep the car and bring it up to spec, you may as well resign yourself to the fact that the braking system needs serious attention before the car goes back on the road. It is both the fiddliest, if you commit yourself to dismantling and re-building it, and most important system on the car (although one could argue the steering system is of equal importance).

Manners maketh the man. The braking system maketh the car!

PS: for stupid money for what it is (about six quid?) you can buy a 'one man' brake bleeding kit - just a pipe with a clip and a one-way (no return) valve that goes on the bleed nipple. Put it on, open the nipple, direct the pipe to a collecting jar, and pump away (to some kind of slow ambient music is the best way!), checking the level in the master cylinder to make sure it doesnt fall too low (and the jar, to make sure it's not overflowing). The expelled new brake fluid, once it runs clean, should be allowed to stand for a day to allow micro-bubbles to escape. Then it can be used for topping up.

Keep asking the questions! The only way to learn.

Post by **bmcecosse** » Fri Aug 14, 2009 9:14 pm

You may have 'braided steel' flexi pipes on the car instead of the normal rubber flexis. However - they don't last for ever - there is rubber inside the flexi sheath - it's just better protected , and braced by the wire braid which stops it expanding when you pressurise the system. Gravity will bleed the brakes when you get to that stage!