Morris Minor Owners Club

After 1.5 ltrs of fluid I still cann't get a decent pedal after changing the master cylinder.
Fluid is comming out of all bleed nipples so it's not an air block.
No bubbles in master cylinder (new Lockheed).
I've currently got car on axle stands with all 4 wheels removed.
All adjusters are turned as much as possible so drums are locked up.
My favorite Mityvac tool doesen't seem to be working so I've had my wife pressing pedal down - once not pumping whilst I undo bleed nipple with a pipe in jar.
Bubbles are rising in jar so there must be loads of air in system.
I had to stop yesterday as I ran out of fluid but was starting to get some pedal.
Today I checked pedal and still way from perfect so I decided to use the Mityvac again - starting on nearside rear.
Disaster as the pedal is terrible again.
This seem to indicate that the rear wheels are causing the problems.

Reading it's a common problem with rear but can fronts cause trouble too ?

Tomorrow it's remove rear drums and see if I can "prime" the wheel cylinders before wasting any more fluid.

BTW changing the master cylinder was completley painless - all fastenings came easilly undone and torsion bar moved out of the way in seconds with a hydraulic body wedge used for pushing panels back into shape in confined areas.

Paul Humphries.

I've got bleeding to look forward to this weekend . I have a completely new dry system having repaced every single part on the brakes except the drums. I am going to fill all the wheel cylinders with a syringe before I start and then work my way round as normal. I'll let you know how I get on.

Roger

paulhumphries wrote:BTW changing the master cylinder was completley painless - all fastenings came easilly undone and torsion bar moved out of the way in seconds with a hydraulic body wedge used for pushing panels back into shape in confined areas.

I could use one of those hydraulic wedgie things. I'm working towards getting the M/C out to have a close look at it but I decided to dismantle the suspension anyway. I have to raise the front and I thought I'd have a look at how it all goes together.

Get a couple of flexi clamps and lock off one part of the system at a time to see if you can narrow down where the problem might be.

Though when I tried mine (on a twin circuit more modern car) it was a bit of a red herring as the problem turned out to be the master, and clamping a line off simply meant the piston didn't travel to the worn out part of the cylinder bore...

Have you tried renewing the bleed nipples? I found that if I turned them enough to bleed, the air was getting drawn in through the threads. (visible in the bleed line but also getting into the cylinders as I pumped the pedal). The temporary solution was to remove the nipple and apply some heavy grease to the top section of the thread (don't grease all the way down as you don't want any ending up in the brake lines).

Packedup wrote:Get a couple of flexi clamps and lock off one part of the system at a time to see if you can narrow down where the problem might be.

Though when I tried mine (on a twin circuit more modern car) it was a bit of a red herring as the problem turned out to be the master, and clamping a line off simply meant the piston didn't travel to the worn out part of the cylinder bore...

Good idea - I'll try blocking off the rear first as I think that is where the problems are occuring.

On my modern car (Chrysler Neon) main agent diagnosed ABS unit had failed. Problem, when I investigated myself, turned out to be the clamp holding the flexi brake pipe had corroded and thus blocking the pipe causing it to retain fluid and keep one brake applied on.
Costs £26 each for two new front flexi pipes (decided to change other anyway)compared to £1500 + fitting + vat for ABS unit
What I'm trying to say is that flexi brake pipes can cause all sorts of problems, without leaking, which is worth noting.

Paul Humphries.

Peetee wrote:Have you tried renewing the bleed nipples? I found that if I turned them enough to bleed, the air was getting drawn in through the threads. (visible in the bleed line but also getting into the cylinders as I pumped the pedal). The temporary solution was to remove the nipple and apply some heavy grease to the top section of the thread (don't grease all the way down as you don't want any ending up in the brake lines).

Actually two of the four bleed nipples were completley blocked (no rubber caps fitted) so I removed them all to ensure they were clear.
I put tiny amount of copper ease on thread but, after your suggestion, think I will now try red rubber grease. I suppose PTFE tape would be suitable - as well as long as nowhere near fluid tract
BTW I've a tub of this red rubber grease (the type you often get with a seal kit) and therefore used some of it under the rubber boot on master cylinder.
Hopefully it'll help stop some of the potential rusting that can occur - the old master cylinder was a real mess in this area.

Paul Humphries.

JimK wrote:I could use one of those hydraulic wedgie things.

did mine back in the spring, all you need is a piece of wood, about four foot long, wedge one end on top of the torsion bar and, pivoting the wood on the cill place a jack under the other end.

when you jack the wood up it pivots on the cill and bends the torsion bar down just enough to remove the mounting bolts.

I've never had a problem using a crow bar or stout screw driver. There may be something about the saloons that makes that impossible, I guess...

I haven't tried, since I needed to adjust the suspension anyway and wanted to dismantle it to learn how it all fits together.

You can avoid any possibility of air being drawn back in past the bleed nipple threads if you do it the tedious (two person) way.

Instead of pumping the brake pedal with the bleed nipple open and relying on the nipple valve, you open the nipple just enough to let fluid out, shout "down" and the second person puts their foot down on the brake and holds it down. When you see the fluid stop coming out the nipple tighten it again and shout "up", whereupon the second person releases the brake pedal, and shouts "up" when it it is fully up. Then repeat until the air stops coming out.

It is useful to use a small child for the pumping part, as they don't get as bored as grown ups. (At least I didn't).

Always used to work, however knackered the bleed nipples were. No need for nasty rubber-dissolving grease near the brake fluid either.

Also, are you doing furthest from master cylinder first? If not, you run the risk of pumping air back from the long run into the short run sections after you've bled them.

Axolotl wrote:You can avoid any possibility of air being drawn back in past the bleed nipple threads if you do it the tedious (two person) way.

Instead of pumping the brake pedal with the bleed nipple open and relying on the nipple valve, you open the nipple just enough to let fluid out, shout "down" and the second person puts their foot down on the brake and holds it down. When you see the fluid stop coming out the nipple tighten it again and shout "up", whereupon the second person releases the brake pedal, and shouts "up" when it it is fully up. Then repeat until the air stops coming out.

No need for nasty rubber-dissolving grease near the brake fluid either.

Also, are you doing furthest from master cylinder first?

Doing all that - two persons / furthest away first managed to get the start of a decent pedal until I ran out of fluid.
I shout "down" and then open the nipple. I then close the nipple before shouting "up".
The red grease is the special type for use on rubber / brake components - difficult to find on car accessory shop shelves.

My plan tomorrow (if rain stops) is to clamp off the back brakes and then rebleed front to confirm if the problem is at rear of car.

Paul Humphries.

bigginger wrote:I've never had a problem using a crow bar or stout screw driver. There may be something about the saloons that makes that impossible, I guess...

I think it's a case of people using what they have to hand / feel comfortable using.
I had the PortaPower set assessable so thought it'd be convienent to use. If I'd had to get it from the back of a shelf (it's a heavy set up) then I reckon a crowbar might have be in my hand instead ;-)

Paul Humphries.

Think I've mentioned this before on this forum but there is always the old trade dodge to cure a spongy pedal when all else fails.

Prop the brake pedal firmly down with a piece of wood and leave it overnight.

It often works ....... don't ask me how

Paul - it wasn't an attack, more something that somebody might find useful People do seem to be far more worried about these bolts than necessary.

bigginger wrote:Paul - it wasn't an attack, more something that somebody might find useful People do seem to be far more worried about these bolts than necessary.

I think I've done it again and written something the wrong way.
In no way, shape or form did I consider anything you said in the wrong way so absolutley no offence taken.
I accept people have been "playing" with Minors for longer than I've been alive yet I've only had my car for a few months.
I'm terrible trying to reinvent the wheel / reverse engineering / looking at alternative ways of doing things.
That dosen't mean I think the way others do things are wrong but that I just do things the way I want.
As long as the end results are the same (hydraulic wedge, crowbars, etc) to move the torsion bars to access the bolts then they are all valid methods.
The world would be a very boring place if we all thought and did things the same way

Paul Humphries.

Have you tried renewing the bleed nipples? I found that if I turned them enough to bleed, the air was getting drawn in through the threads. (visible in the bleed line but also getting into the cylinders as I pumped the pedal). The temporary solution was to remove the nipple and apply some heavy grease to the top section of the thread (don't grease all the way down as you don't want any ending up in the brake lines).

The Minor bleed nipples were never intended to hold a vacuum when opened. Any system that fills the brakes using a vacuum is something I'd avoid using on a Minor.
If you use something like an easibleed (uses air pressure to force fluid from the m/c into the system) then you may find it a bit easier to bleed.

sadly there could be many other reasons why you are having problems. I replaced a m/c on a Minor 2 years ago using a Delphi/Lockheed one, and this was the only car where I never managed to get a good pedal
After 2 years the (fairly new) m/c had to be replaced again and then the car was then ok

If in doubt, block the front or the rear feed with a bleed nipple to see if the front or rear is the worst area. If they both seem bad it is very unlikely - but not impossible - that the new m/c is faulty.

Sods law says there is nobody around today to help me so I haven't been able to try bleeding again
I used a proper hose clamp on the rear flexi and after a couple of pumps the brake pedal went hard proving the bulk of the problem is with the rears.

Other than Easybleed (I've got one somewhere but a friend borrowed it and I've never managed to get a decent seal at the plastic bottle since - sprays fluid out everywhere) what one person bleeders do people use on Minors ?
I normally find a Mityvac works but this is the first time I'd had to resort to the two person method in years.

Paul Humphries

I have found fitting new pparts to a brake system nearly always causes problems, the chances are its n air lock in the mastercylinder.I havent personaly got around to bleeding a moggy system but had a lot of experience with other systems. If you can you need to prime the mastercylinder and make sure it is full of fluid before fitting up. It can also be done by pumping fluid in to the system from the wheel cylinders with a big syringe. The vac bleeders tend to draw air in from the threads of the bleed nipple

I normally find a Mityvac works

What is a Mityvac