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Brake problem - poor pedal


adrian

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I have fitted a new brake system to a series 2 and now I can't get a decent pedal.

I have fitted a new CV master, all new slaves, shoes, copper pipe and hoses.

I have bled the system many times using various methods, I'm pretty confident there is no air in the system. 10 litres of fluid used!

I am on the third master cylinder - cheap steel, expensive steel and now alloy.

I'm on the second set of slaves, cheap first time and now expensive.

The shoe return springs are in the right place, checked and rechecked.

The brake adjusters have been wound out and backed off two clicks.

When I first press the pedal it goes to the floor, then on the second stroke I get a firm pedal half way down like it should be.

I'm now into weeks of deliberating, rechecking and hair brained ideas (such as parking the vehicle on a 45 degree slope for two weeks with a stick on the pedal).

Has anyone heard of or know of a solution for this problem, or am I missing the obvious?

Thanks

Adrian

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Have you set the brake pedal height as per the book ?

Have you set the free play correcly at the master cylinder ?

These two items are the first you must check.

Try setting all adjusters all the way up and see if you have a good pedal.

Then try one click backed off and compare.

Clamp brake ppes in turn - flexi ones and see how things change.

Following that I'd have a look at the " Series 2 club " forum as there is a masive amount of brake related information there. ( I'm of to work now ).

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Have you set the brake pedal height as per the book ?

Have you set the free play correcly at the master cylinder ?

These two items are the first you must check.

Try setting all adjusters all the way up and see if you have a good pedal.

Then try one click backed off and compare.

Clamp brake ppes in turn - flexi ones and see how things change.

Following that I'd have a look at the " Series 2 club " forum as there is a masive amount of brake related information there. ( I'm of to work now ).

Height correct.

Free play correct.

Even with the adjusters right up the pedal is bad.

With all the hoses clamped the pedal doesn't move at all, with both fronts off and the back clamped it feels good, clamped the other way its good. With no clamping it's bad, which sort of implies the problem is at the slaves.

Are they really that difficult to bleed?

Thanks for your pointer to the Series 2 club, looks like a fantastic resource.

Adrian

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Clamp all the hoses and find out by elimination where the trapped air is.

If this is on TLS front brakes you want the front shoes & drums off and G clamps holding the pistons fully in to reduce the cylinder volume. Plus use a pressure bleeder so the trapped air is carried out rather than shuttling about when bleeding.

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Clamp all the hoses and find out by elimination where the trapped air is.

If this is on TLS front brakes you want the front shoes & drums off and G clamps holding the pistons fully in to reduce the cylinder volume. Plus use a pressure bleeder so the trapped air is carried out rather than shuttling about when bleeding.

Progress report - I have clamped all the hoses within an inch of the unions, master cylinder end. Employed Samson's legs (both of them at the same time) to press the pedal. Result - The pedal wouldn't move at first, but then gave moving to the half way point. The sort of feel you get when you blow up a balloon. I released the pedal it returned to the top and then was rock solid. I had to remove on of the clamps to get it to move.

I have repeated the process with the hoses clamped at the slave end, this time using a very hard push I can floor the pedal.

I'm guessing this might indicate one or more faulty hoses?

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You may find that the flexihoses expand when you force the pedal to the floor.

I had a hell of a job bleeding brakes on my S3 - went through a 5 litre bottle of fluid over 2 weeks and nearly pulled most of my hair out. In the end, used a pressurised brake bleeding kit, with someone pumping the pedal very hard and fast at the same time. Jets of brake fluid all over the place! But it worked... :D

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Got the same problem with mine. Replaced all the slaves for quality ones. Replaced MC for genuine, replaced hoses for braided, replaced shoes, replaced all adjusters, pipes and removed the shuttle valve.

Still a spongy pedal.

Used the traditional brake bleed method, the vacuum method and syringe method - still a poor pedal.

Checked the drums and theyre within tolerance and nicely round. Checked the backplates were firmly secured.

I HATE! Series brakes, they're carp beyond imagination. I would love to know how Land Rover did it as they left the factory.

/rant

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You may find that the flexihoses expand when you force the pedal to the floor.
That could well be a problem, as could faulty shoes with incorrect camber - if the curvature is wrong, the pedal force gets lost in deforming the shoes insead of applying direct pressure. Some of the pattern shoes are well off the correct camber.
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So I have now replaced the flexible hoses with braided, don't they look lovely.

Brakes still bad.

I offered the shoes up to the drums and they looked quite good, could I be looking at a bedding in issue?

How can such a simple set up be so difficult to get right!!!

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I've been having the same problem with my Hybrid with a remote servo after a wheel cylinder let go ruining my shoes. I then bled the system for ever and gave up. Took Nelly for a ride round the block crash stop,solid pedal, four black stripes and no pulling. So try running the engine to to set the servo vacuum, then give it a try. Mine has the bigger LWB brakes and on the front twin cylinders and bleeder on lower cylinder which makes the "bleeding" problem worse.

I also made the mistake of not setting the master cylinder clearance right when I built the beast, interesting effect, pedal got harder and harder and eventually locked the wheels up as the fluid couldn't return to the reservoir. Could be a novel way of bleeding brakes single handed!

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  • 2 weeks later...

Update.

So after replacing the brake hubs, shoes, springs and snail adjusters with some 'quality' new ones they still were not right!

Found some fluid under the rubber boots of the slaves, took them to a different parts dealer who suggested the leaking was caused by alloy castings with steel pistons and the rubber of the seal reacting. So new all steel slaves fitted. Nipples greased with red grease to stop air passing the threads.

Following loads more bleeding and a technique involving opening the nipple and winding the snail adjuster in and out - with no pumping - they came up firm and passed the MOT. A miracle has occurred. No logical explanation and I'm not looking forward to doing this again.

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  • 2 weeks later...
Next time you need to do this job nip in to C&D motor parts in colley lane and pick up a gunsons pressure bleeder - its a cheap way of pressure bleeding the system and cured all my braking problems

An old trick with brake bleeding a series is to jack up the front end as high as you can this removes the air from the master been doing this for 30 years never had a bad pedal yet

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  • 2 weeks later...
An old trick with brake bleeding a series is to jack up the front end as high as you can this removes the air from the master been doing this for 30 years never had a bad pedal yet

You don't say if it's an 88 or a 109.

88 try the above

The 88 is quite straight forward to bleed compared to the 109.

109

I had to remove the front drums, and shoes, pushed in the slave cylinders and clamped them in place the re-bleed the system. Also I have in the past pulled the back plates off, with the shoes clamped in place, tipped them upside down, so the bleed nipple is at the top and bleed them. A lot of hassle but it does work

:)

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109

I had to remove the front drums, and shoes, pushed in the slave cylinders and clamped them in place the re-bleed the system. Also I have in the past pulled the back plates off, with the shoes clamped in place, tipped them upside down, so the bleed nipple is at the top and bleed them. A lot of hassle but it does work [/b]

:)

Thats the only way I have ever managed to bleed the brakes on my S3.

Daan

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  • 7 years later...

Hello all. Same issue here, but have found a solution to the problem.

Customer came in with very poor brakes, that even the left show had worn down to metal and right cylinders were leaking.

Since the 109 has two cylinders with the bleed port at the bottom, my brain had a fart and said that wont work, there is no way to get the system bled correctly. So i went on a mission to redesign the setup.

Here what i have done.

I removed the hub.

20160930_092341_resized_1.jpg

This picture is showing where the bleed port cylinder is located (marked with white X).

20160930_092658_resized_1.jpg

Next I unbolted the backing plate and turned the bottom cylinder towards the front of the vehicle.

20160930_093308_resized_1.jpg

 

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20 hours ago, R3D3ZYN said:

This shows the bleed port (facing upwards!!!)

20160930_093349_resized_1.jpg

The the last thing you need to do is remake the brake lines and hey presto...

20160930_093414_resized_1.jpg

That's going to make it worse.

I thought you were going to do what I did - remove the back plate, lay it on top of the swivel with the shoes down and pipes on top so that the air was against the ports, then bleed and refit.  That works perfectly, and only needs doing if you have introduced air into the system - it isn't needed for periodic fluid replacement.

The PDWA valve is another major source of trapped air.  I recommend removing it and connecting the lines, and using a Defender/Discovery/RRC reservoir cap with float sensor - it gives earlier warning of a leak, senses small leaks, doesn't seize and doesn't make bleeding a pig.

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Well just to let you know, it bled up first time with no problem at all. And this way I can change the fluid at anytime without moving the backing plate over and over. I do see where your coming from, but I hate taking stuff off the car just to do a simple job. Cheers for the comments.

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Are you now going to use the brakes with the slaves at 3 and 9 o'clock? If so, what you are doing is potentially dangerous. The braking system is designed for leading and trailing shoes to maximise brake pressure and efficient braking if the system is well maintained. Altering the pipework to ease maintenance is one thing, but doing that might well be altering the brake efficiency of the vehicle. A few years back a forum member 'botched' his brakes and some of his family died as a result. He's now in prison and his life is ruined. You can leave the brake shoes and slaves in factory spec position with just a minor alteration to the pipework which has no effect at all. Jeez - bent pipes and a seemingly dirty job just looks so bad.

 

 

Les

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Couldn't you even be bothered to wash the mud and rubbish away before stripping to keep the muck out of the pipework or seat the backplate and bolts correctly?  Just how do you propose to bleed the aft cylinder, with the entirety of the cylinder above the unions?  The pipes don't really help with topping up the swivel housing, like that, and you have made them dangerously exposed to off road damage - there is a reason that LR had the pipe tucked in tight against the back plate.  It's not Land Rover's finest design, but altering it opens up a massive can of worms, but what you have done causes more trouble and cures none.  Strip them back off, clean everything up so it'll fit without trapped dirt, and then refit it correctly before it bounces back on you.  Like Les said, modified brakes have landed the modifier in prison on numerous occasions.

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I have seen these problems turn up for decades!  Long wheel base Land Rover brakes can be a nightmare to bleed if you don't get it right.  Alternatively, they are very straightforward, though time-consuming, if all is well.  However, there is absolutely no need to go changing the original layout!!  Here's a few tips I've picked up.

1) You will never bleed these brakes successfully if there is a sticky piston in a wheel cylinder (in this case it's all new so shouldn't be an issue).  Likewise, it's important that the distribution valve is okay and that you don't have rubber hoses which look good but are collapsing inside or bulging under pressure.  True for any car, of course.  Land Rovers also have a small risk of steel hoses being pinched, though that would have to be bad to affect bleeding.

2) It is theoretically possible to trap air in the master cylinder.  As long as the car is level or slightly front up that shouldn't be an issue.

3) Generally, all you have to do is back off ALL the brake adjusters before you bleed.  This is the opposite of what most people do though!  The reason you back them off is that this gives the pistons maximum travel.  That means, as you bleed, the cylinders on the other free wheels store a lot of fluid, which gives the air in the cylinder you are bleeding a really good push.  If you wind up the adjusters, you really will have endless trouble trying to bleed those brakes.  People really struggle to get their heads around this but you absolutely have a Eureka moment when you find how well it works.  Truly.

3a) Don't forget to readjust your brakes once the air is out!!!!

4) If there is still a problem, leave the adjusters on the other three wheels backed off but wrap a strong strap around the shoes on the tricky wheel to prevent the cylinder (s) opening Doing this leaves a smaller volume that needs displacing to bleed that particular wheel, that's all.  It shouldn't be necessary but it does give you a boost.  It goes without saying how careful you have to be doing this - brake hydraulics exert a lot of pressure, so the strap needs to be strong and very secure and preferably wrapped around twice.

5) It should go without saying that you bleed from the furthest wheel back to the nearest and there is no harm, if lots of components have been changed, in doing this circuit twice.  If a second bleed hasn't worked, you are just wasting fluid - find the problem.  Good technique will have you using a snug-fitting clear hose, pushing fluid into a jar - but you already knew that!  Finally, it's helpful to have three people, one pumping fluid through, one checking the level, one opening and closing the bleed nipple (ideally, you close it while the assistant's foot is down, though having a fully bled cylinder connected to a tube and jar etc. means you shouldn't suck any air back in if you don't).  Nothing like good, strong pumps to get that fluid pushing air out.

6) I have got very angry at times trying to sort Land Rover brakes.  It's no longer a problem.

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