Clutch and Brake Master Cylinders.

[kevin50]

Please Forgive me but Struggling to get these dam things set up right, just cant  get my head round it. 

On with Series rebuild  this is where I am at , clutch and brake parts are all brand new parts from rear to front shoes cylinders drums pipes fittings ect,   new clutch  , fork slave, all pipe work, and both masters are also new.

No fluid in yet,  trying to get them adjusted so I can get fluid in and bled ,

I can get the peddles at the correct height but just  cant  get how to get the 1.5,mm play when adjusting the 2 locknuts, looked at loads of  writeups and vids but where exactly on the rod does the free play have to be ? does it have to be spot on  ?

Just want it done right before fill with fluid  and connect everything up  to bleed. 

Thanks

[Snagger]

There should be an aluminium shim between master cylinder and pedal box, at least on the clutch.  I never realised what that was for, but it must be for ethics issue..

The operating rod should have a little play on pedal release to ensure the master cylinder depressurises and to allow it to refill.  It is essential.

You may need to make up mounting shims or you could just use a tap and die set to extend the threads further up the operating rod.

[kevin50]

10 hours ago, Snagger said:

There should be an aluminium shim between master cylinder and pedal box, at least on the clutch.  I never realised what that was for, but it must be for ethics issue..

The operating rod should have a little play on pedal release to ensure the master cylinder depressurises and to allow it to refill.  It is essential.

You may need to make up mounting shims or you could just use a tap and die set to extend the threads further up the operating rod.

Never seen or heard of shims in there before. 

[simonb]

You need to fill with fluid and bleed, then set the pedal height and free play on the rods after that. The reason is that the master cylinders and their seals won't be in the final "rest" position unless there is fluid in the system.

The 1.5mm free play is best measured by using a pair of pliers pulling/pushing on the rod after the pedal height has been set - and system bleed. Slacken off the push rod nuts to do this. You are looking to set a bit of slack in the rod so it moves inwards about 1.5mm when the pedal is at rest, before you feel the rod touching the back and moving the cylinder.

There needs to be some slack to allow the master cylinder to re-cupricate. If you don't, the master cylinder won't fully release the wheel cylinders and the brakes will bind.

On the clutch, if pedal height and free play aren't correct, there won't be enough throw on the slave cylinder and the clutch plate won't disengage fully.

Edited July 7, 2022 by simonb

[kevin50]

3 hours ago, simonb said:

You need to fill with fluid and bleed, then set the pedal height and free play on the rods after that. The reason is that the master cylinders and their seals won't be in the final "rest" position unless there is fluid in the system.

The 1.5mm free play is best measured by using a pair of pliers pulling/pushing on the rod after the pedal height has been set - and system bleed. Slacken off the push rod nuts to do this. You are looking to set a bit of slack in the rod so it moves inwards about 1.5mm when the pedal is at rest, before you feel the rod touching the back and moving the cylinder.

There needs to be some slack to allow the master cylinder to re-cupricate. If you don't, the master cylinder won't fully release the wheel cylinders and the brakes will bind.

On the clutch, if pedal height and free play aren't correct, there won't be enough throw on the slave cylinder and the clutch plate won't disengage fully.

Filled the clutch master up tonight  tried to bleed it on my own with one of those halfords ezzy bleeds, it worked a treat when I used it on defender brakes last year but couldnt get it to work on clutch just running straight through before I could nip it up. . pedal was very heavy.

Anyway after a bit of googling  I reverse bled it with a syringe, still not sure if it is right , still quite heavy,  got a mate who drives a series will get him to check it when he comes. 

Pedal height correct and sure the  freeplay is as near as dam it so will see.

Dreading doing the brakes do I do  the same as clutch ? no nut to adjust pedal height , can  I do it with the 2 lock nuts ?

[Snagger]

My 109 had a shim on the clutch master.  The condition of the master and shim and the accuracy of the cutting of the shim show it was fitted at the factory.  I wouldn’t want to guess how common they were, and it may have been a foreign spec issue as mine had a few details that suggested it was part of a cancelled export order.  But the shim was there.

[simonb]

Land Rover clutches are a bit heavier than a modern car, but shouldn't be too heavy. You did use a small amount of grease on the clutch driven plate splines before you fitted the gearbox?

On the brakes, clamp both front hoses. Get the rears bled first. Then clamp the rear hose and unclamp and bleed each front wheel. Once you have one front done, clamp that hose and do the other. Adjust the shoes hard up against the drum before you start to bled, and adjust after bleeding and before the final push rod adjustment.

You don't say what model you series is, single front wheel cylinders aren't usually a problem but twin cylinder/11" fronts can be a pain. Plenty of posts on the forum about those. My SWB has that brake set up, clamping the hoses and pushing the brake pedal down swiftly works better to shift the air, than slow pedal stokes.

Set the push rod nuts approximately to get started and then once bled, adjust properly. The adjustment of the push rod can make a huge difference to the feel of the brakes once bled. If its incorrect, the pedal will sink to the floor quickly or need a couple of pumps to feel hard. Once correct, a single push down should give a hard pedal about halfway down its travel.

[kevin50]

1 hour ago, simonb said:

Land Rover clutches are a bit heavier than a modern car, but shouldn't be too heavy. You did use a small amount of grease on the clutch driven plate splines before you fitted the gearbox?

On the brakes, clamp both front hoses. Get the rears bled first. Then clamp the rear hose and unclamp and bleed each front wheel. Once you have one front done, clamp that hose and do the other. Adjust the shoes hard up against the drum before you start to bled, and adjust after bleeding and before the final push rod adjustment.

You don't say what model you series is, single front wheel cylinders aren't usually a problem but twin cylinder/11" fronts can be a pain. Plenty of posts on the forum about those. My SWB has that brake set up, clamping the hoses and pushing the brake pedal down swiftly works better to shift the air, than slow pedal stokes.

Set the push rod nuts approximately to get started and then once bled, adjust properly. The adjustment of the push rod can make a huge difference to the feel of the brakes once bled. If its incorrect, the pedal will sink to the floor quickly or need a couple of pumps to feel hard. Once correct, a single push down should give a hard pedal about halfway down its travel.

Thanks gonna give it a go, one thing to mention is the whole system is completely  empty, whats the best way to fill first before bleeding. do I just keep topping MC up untill it starts coming through each corner ?

Edited July 8, 2022 by kevin50

[simonb]

Yes, fill the master, you should get about 4 or 5 full pedal stokes before it empties, but keep an eye on the level, you don't want it to empty.