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Brake problem - poor pedal


adrian

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On 10/1/2016 at 11:05 AM, Les Henson said:

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

Hello Les,

Yes the cylinders are staying at 3 & 9. he brake shoes are NOT leading and trailing as they are both the same (as single cylinder slaves only push one direction) I have tested the brakes on a brake machine and they got up to 310 daN. Regarding the pipe work.... the picture was the old piping, so yes it's dirty... the new piping is not.

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On 1/10/2016 at 5:41 PM, Snagger said:

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.

Hello Snagger,

1. Yes we have washed the backing plates, replaced all four front cylinders, all shoes and drums. The picture I took was just to show everyone what I had done.

2. The brake fluid comes from the hose, through a new pipe into the rear lower hole of the cylinder, goes through the cylinder and across the new pipe to the front lower hole, through the cylinder and out the bleed port.

3. New pipes have been made so that the swivel hosing filler has complete access, and the pipes are not going to get hit as they are at the back of the backing plate and make there way over the top.

20161005_125142_resized.jpg

20161005_125219_resized.jpg

4. I have looked at both yours and Les's comments about modifying the brakes and being landed in prison...

So I called a vehicle modification inspector and he had a look this afternoon... which to reply, there was no issue in safety as all equipment is original and all I had done was relocate the cylinders. He looked at my bracket on the top and said there was no need to have it but it does secure the pipe better. He even drove it around the block, did his usual checks like braking on corners and uneven surfaces, then tested on the brake machine like I did.

I'm not here to make you all mad or enemies, just trying to help make everyone's life easier.

If you don't agree with what I have done... I don't have a problem. Regards and good luck with your brakes.

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On 2/10/2016 at 6:49 PM, deep said:

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.

Hello Deep,

Yes I like the way you explained the procedure. I used to have so many problems and sometimes it took hours to get it correct.

This is why I redesigned the layout. I can fully adjust the brake (as you would normally with any other vehicle) and then bleed the braking system by myself if required.

I don't need anything special other than a tube in a bottle like you mentioned.

But to let you know, I did have one other person with me while doing it though as it's easier... And as I had mentioned before it came up first time with no issues at all and works great. So my job that used to takes sometimes hours will only take me half an hour if I have a coffee after 15 minutes.

Thanks for the comments.

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On 30/09/2016 at 1:12 AM, R3D3ZYN said:

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

 

20160930_093414_resized_1.jpg

If you cleaned the parts for the work, why are they so filthy on the reassembly?  You should be able to see why I'm concerned about the cleanliness of the job from this photo, where dirt ingress to the hydraulics is a major risk.  It upsets me when I see DIY owners cut corners over job cleanliness on tasks like this, and I really get cross with professionals risking their fee paying customers welfare to save five minutes.  I still don't understand what led you to think this reorientation could possibly lead to easier bleeding, and blocking of the swivel housing oil plug and the increased threat to brake line damage are plainly obvious.

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The pipe on the right is too short, so you would have to replace it anyway by the looks of it, so you have gained nothing. Re-piping it seems to be easier and a far better option than what you have done (how often do you need to bleed a braking system anyway once it's done?).
You say Vehicle Modification Inspector, What is one of those? I googled it extensively and nothing in the UK came up. Is this person a government approved inspector that then supplies some kind of paperwork or certificate that your customer and insurance company will accept? Does your customer know or previously agreed to his brakes being modified in this way and has spoken to his insurers before hand? I think if he told his insurers that the brakes had been altered they would want some kind of official certificate to state that they are still within acceptable limits. You also say a 'brake testing machine' what exactly did you use ?

 

 

Les

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On 7/10/2016 at 11:41 PM, Snagger said:

If you cleaned the parts for the work, why are they so filthy on the reassembly?  You should be able to see why I'm concerned about the cleanliness of the job from this photo, where dirt ingress to the hydraulics is a major risk.  It upsets me when I see DIY owners cut corners over job cleanliness on tasks like this, and I really get cross with professionals risking their fee paying customers welfare to save five minutes.  I still don't understand what led you to think this reorientation could possibly lead to easier bleeding, and blocking of the swivel housing oil plug and the increased threat to brake line damage are plainly obvious.

Well you are obviously not reading the full forum as I have posted a picture of the cleaned backing plate etc... just above ^^^^^^^^

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1 hour ago, Les Henson said:

The pipe on the right is too short, so you would have to replace it anyway by the looks of it, so you have gained nothing. Re-piping it seems to be easier and a far better option than what you have done (how often do you need to bleed a braking system anyway once it's done?).
You say Vehicle Modification Inspector, What is one of those? I googled it extensively and nothing in the UK came up. Is this person a government approved inspector that then supplies some kind of paperwork or certificate that your customer and insurance company will accept? Does your customer know or previously agreed to his brakes being modified in this way and has spoken to his insurers before hand? I think if he told his insurers that the brakes had been altered they would want some kind of official certificate to state that they are still within acceptable limits. You also say a 'brake testing machine' what exactly did you use ?

 

 

Les

1. Well you are obviously not reading the full forum as I have posted a picture of the new pipe work... just above ^^^^^^^^

2. Yes a Vehicle Modification Inspector... when I google that it brings up heaps around the world. Try these guys...http://www.eliteinspections.co.uk/services/supercar-modified-car-inspections/

3. Yes the inspector works towards the government, and yes they do give a certificate to both the customer and in the governments computer system.

4. The brake machine is like a rolling road, but it records the performance of the brake per wheel. http://www.bmtest.dk/Default.aspx?ID=9

Any mechanic should know of all these things.

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13 hours ago, R3D3ZYN said:

Well you are obviously not reading the full forum as I have posted a picture of the cleaned backing plate etc... just above ^^^^^^^^

The photos that YOU posted showed filthy swivels and back plates.  If you claim they are clean, then I hate to think of what you consider dirty..  The rotation of the back plate you posted as a solution to the bleeding issue can have no positive effect on bleeding - it may help one cylinder but is going to worsen the other (specifically the cylinder with the upwards pointing piston).  Be realistic - if you come into a forum as a new member, citing your professional credentials, showing dirty and poorly considered work, don't be surprised to draw flak, especially when using a login name that does the modern, young, trendy but irritating thing of misspelling a word.

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Aside from the issues of what appears be a dirty job, I'm REALLY struggling to understand why you have taken this route in order to just bleed the brakes more effectively (how often do you need to bleed brakes). The bleed nipple still in the best position, which is at the highest point of the wheel. All that work and I guess the expense of it (I guess vehicle Modification inspectors charge).
You can do it easier, quicker, possibly safer, in a cheaper way by just altering the pipework -

11-inch brakes 02.JPG

11-inch brakes 01.JPG

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  • 4 months later...

Hi, I am intrigued by some of the issues raised here. I am in the process of replacing and renovating my TLS front brakes.

They are on an 88 chassis and were leaking and filthy and therefore worth sorting!

I have all new cylinders, shoes and rear pipes all sorted out Left and Right, so far all good. After repiping the cylinders with new preformed pipes it is apparent that the preformed pipe on the lower cylinder is impeded by the lower swivel pin.

Options are, a) to deform the pipe to allow true 12 and 6 o'clock orientation of the cylinders, b) rotate cylinders to 10 and 4 o'clock thus no contact between pipes and swivel pin or c) bin preformed pipes and make up pipes to fit.

Having read through the posts I realise that option b) is non standard (on removal they were 12 and 6 o'clock) but why would it perform less well than standard ?

I am not concerned by bleeding issues as I will remove and go with the horizontal method!

 

 

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Thinking it through I know what I have done. I test fit the new cylinders and pipes on the backplate without replacing the the stub axle, hence bringing the new pipes into contact with swivel pin

Back to it - sorry for any ranting that was coming my way !

 

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In my opinion the original poster of this thread was doing something potentially dangerous by altering the manufacturers design of the braking system, doing unnecessary work for no reason, and in an unprofessional manner by poor workshop standards. I have worked on cars for many years and I have never come across a vehicle that has brake shoes at the top and bottom, so there's something obviously wrong with doing that. Relocating the bleed nipple is a completely different thing and merely makes bleeding the brakes easier than trying to do it in the original position. As far as I know - you can't buy pre-formed pipes to do what I have pictured, so you will have to get them made or do it yourself.

 

 

Les

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You have said you've used a CV type Master Cylinder.  I would make sure it's the right one - there were two, with different swept volumes.  My guess would be you've got 90-569126 rather than 90-569128?

Post a photo of your master cylinder - they are easy to identify!

Si

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  • 3 months later...
On 2016-9-30 at 11:05 PM, Les Henson said:

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

Nothing wrong with twin leading shoe brake cylinders at 3 and 9 o'clock, classic Minis with 10" wheels and TLS drums did that up front, Morris Minors have shoes top and bottom both front and rear, as did many other old cars.  To be fair, he's made brake adjustment more awkward, and his pipework looks vulnerable to damage if a spanner slips topping up the swivel oil, which I don't like. Especially since you need to do those more often than brake bleeding. Nothing inherently dangerous about the mod itself, he could have shaped the pipework better though.

Your own revision is neater and easier.

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