Brakes ...

[David]

Well I've stripped out the rear brakes, a couple of things to note;

- the offside wheel cylinder input pipe was siezed and the fitting rounded, luckily I could get the cylinder and pipe off in one piece and removed the pipe on the workbench
- the Marina Haynes manual says the top port is for the transfer to near side wheel pipe but thats reversed on mine, does anyone know if the in and out of the wheel cylinders is important(daft question!)

So whilst the pipe is good the fitting is knackered so I need to find someone in High Wycome to make a new pipe with fittings for me, does anyone have any recommendations?

[stevejgreen]

Re: Brakes ...

If bleeding from the furthest cylinder first, the bleed nipple must be highest. For an intermediate cylinder, it's feed from the master cylinder must be at its lowest.
The idea being that no air can be trapped in the system.
Rather like bleeding a Marina clutch, you are wasting your time if you do not bleed from the highest connectin on the clutch slave.

[David]

Re: Brakes ...

If bleeding from the furthest cylinder first, the bleed nipple must be highest. For an intermediate cylinder, it's feed from the master cylinder must be at its lowest.
The idea being that no air can be trapped in the system.
Rather like bleeding a Marina clutch, you are wasting your time if you do not bleed from the highest connectin on the clutch slave.

That makes good sense, so can I assume that the fluid can go in and out either port on these Marina (Morris/Triumph) cylinders?

[stevejgreen]

Re: Brakes ...

Rule of thumb: In at lowest, out at highest, whether final or intermediate slave cylinder.

[David]

Re: Brakes ...

More on the brakes...

I finally got the new wheel cylinder in place (Marina axle) it wasn't easy getting the two steel clips in place behind the drum (one sprung) and now that I have the cylinder doesn't slide in the slot in the drum easily, is it supposed to?

If I tap the cylinder with a mallet it does move, but then the clip holding the sprung clip in place ops off the dimples and slides as well.

Maybe I have to remove it and properly clean and wet and dry the back plate so it's free of an corrosion, re-grease and try again.

Anyone had similar experiences with the Marina wheel cylinders?

thanks,

David,

[stevejgreen]

Re: Brakes ...

The rear brake slave cylinder is designed to slide. It enables equal pressure to be applied bo both brake shoes should they wear unevenly. It should slide relatively easily, but not loose!, a mallet is far too much pressure. It sounds as if you need the use of a wire brush on the back plate.

[David]

Re: Brakes ...

Thanks Steve. There's a lot of scope for movement but I doubt the wheel cylinder will move far with the brake lines attached to it!

Will strip it again and clean the back plate more thoroughly.

[stevejgreen]

Re: Brakes ...

If you have auto adjusters the slave cylinder can move further. The copper pipes can take up quite a lot of movement. 1/8" easily.
Its a very gradual move when in service, not a step change.

[David]

Re: Brakes ...

Well everything is back together, the offside wheel cylinder is very tight in the backplate but I think it's moving when it needs to.

However, who invented these automatic adjusters? What a terrible piece of engineering, the offside arm is not locating in the adjuster ratchet wheel so pulling the handbrake is not adjusting anything.

Has anyone worked out how to adjust these with the drum in place? Seems like that's impossible.

Finally, was there an adjuster for the handbrake cable on a hybrid, did it use the Marina bracket or is it on the handbrake? I will have to try and find it tomorrow.

[greyV8pete]

Re: Brakes ...

Well everything is back together, the offside wheel cylinder is very tight in the backplate but I think it's moving when it needs to.

However, who invented these automatic adjusters? What a terrible piece of engineering, the offside arm is not locating in the adjuster ratchet wheel so pulling the handbrake is not adjusting anything.

Has anyone worked out how to adjust these with the drum in place? Seems like that's impossible.

Finally, was there an adjuster for the handbrake cable on a hybrid, did it use the Marina bracket or is it on the handbrake? I will have to try and find it tomorrow.

I had the lever and ratchet type of automatic adjusters on my old Mk2 Cortina. The common fault (even by garages) is to tighten the handbrke to make it work better - like for an MOT pass. Wrong!

When the handbrake is fully off at the H/B lever inside the car, the lever inside the drum that adjusts the ratchet wheel MUST BE fully back against the back plate stop.

Best way to set this up is to remove the clevis pins at the end of he handbrake levers. Then ensure that the lever is fully back against its stop by pushing the lever manually towards the backplate. Then < with the handbrake lever in the fully off position, adjust the length of the cable at the clevis until the clevis pin just goes in without moving the lever off the backplate. The adjusting lever can then make full travel and automatic adjustment occurs. On refitting the drums several pulls of the handbrake are then required (until you don't hear the ratchet clicking under the lever) for the brakes to be adjusted fully.

That said. The ratchet wheel needs to be coated with coppaslip grease where it fits into the wheel cylinder. The whole assembly must be kept lubricated and free from dirt build up. I used to find that the intervals that I needed to do this were about the same as that needed to manually adjust the rear brakes on my old TR3A so there seemed little benefit! Peter.

[stevejgreen]

Re: Brakes ...

In my experience MOT testing garages take the easy route out. Either adjusting handbrake cables or replacing them because they have stretched(?), rather than inspecting the auto adjuster mechanism, that rarely features in workshop manuals. Its glossed over in all the Marina - Ital Workshop manuals that I have seen.

[David]

Re: Brakes ...

Thanks Pete, that's very useful information.

[David]

Re: Brakes ...

Well, all back together. I carefully filed the 'feet' on the back of the cylinder down about 0.3mm to reduce the tension on the assembly when mounted through the backplate, cleaned up the groove in the cylinder (that holds the U clips) and rounded out the open ends so I could get the U clips in easier. Then a wire brush attachment on the drill to clean the slot in the back plate. Followed by copper ease.

It's all back together but I did brake the spring steel auto adjuster (that moves the ratchet) off the handbrake lever whilst trying to bend it back into shape(yes I know spring steel only bends one way!), no idea how it got out of shape initially but it had to be tried because it was chaffing/scratching on the inside of the drum. I'll just have to whip the drum off every few months to manually adjust them.

So I just have to go back after dinner, bleed the brakes and find out where the handbrake adjuster is then I think I'm done!

Thanks for the help from everyone.