Rear brakes - 1980 Californian

[Mokee Moke]

G'day all,

Refurbishing the rear brakes on my 1980 Californian but it appears the setup is not standard. According to my parts supplier, rear wheel cylinders should be 11/16in, but the ones fitted are 3/4in.

I tried to fit the new 11/16in cylinders, but the locator pin won't match up with the backing plate.

Looking for advice please on what is standard for 1980 Moke rear wheel cylinders and backing plate. It appears the backing plate has been modified to fit, looking at the elongated holes for the mounting bolts. Photos of parts removed follow.

Part numbers on removed parts:
- backing plate = Girlock K361-002-LH
- wheel cylinder (3/4in bore) = R52

[Terry]

Hi,

a picture of the cylinder you are trying to put in might be useful.

The rear cylinder can be determined by whether you have drums or discs on the front.

Looking at your backing plate  it already has been modified to fit the different cylinders, normally there is only one hole next to the bleeder hole for the locator pin and the bleed hole has been filed.

Normal fix is to drill or file out the  hole closest to the pin until it fits. Not ideal but the supply of rear brake cylinders are limited and the ones I get, LPR, don't make a left and right , just one size fits all.

Terry

[Mokee Moke]

Terry, my supplier's source is LPR too.




(had a few strikes of the hammer....)

[Mokee Moke]

Disc front end

[Mokee Moke]

G'day All, an update on my brake overhaul.

I have replaced nearly everything in the system, but as yet don't have a brake pedal that i am happy with, nor am I able to get the handbrake to hold.

*Brake pedal. Adjusted the (new) rear shoes up snug to the (new) rear drums. Have installed new front callipers and pads. Bled all four wheels until free of air. Car pulls up when applying the brake on first application, but pedal almost touches the floor. A quick second application (i.e. second pump) and the pedal sits higher (and the wheels lock up).

*Handbrake. Have replaced both cables and adjusted the cable tensioning nuts as per manual, but handbrake does not hold car on a slope.

I have read quite a number of previous threads on brake bleeding, and have tried the same tips. But not having much success. Any thoughts?

Thanks,
Greg

[yellaterra]

   As a simple question, when you say you rebuilt the whole brake system on your moke did you fit the rear brake proporsioing valve back into the system?  You say the pedal nearly goes to the floor but you can pump it up. Maybe it’s not holding the brake line pressure as it should?  Other members may have more corrective measures if this is the problem.

[Maddog]

Hi Mokee,

Being able to pump up the brakes to get a better pedal is usually a sign of bad adjustment. Air in the system would give a spongy pedal.

With the rear, did you adjust them with the handbrake cable disconnected? Turn the adjuster until the brakes are locked hard and then back off until the wheel turns freely. Then adjust the cables until you can drop the pin back in at the wheel.

With everything being new I reckon you will have a bit more pedal travel until it all beds in, but it should be consistent and shouldn't go near the floor.

Cheers, MD.

[Terry]

Hi,

another diagnostic step is to adjust up all for wheels so that they are locked up tight without your foot on the pedal at all. A good way to do this is to have someone hold the pedal down and while you go around and adjust everything up tight.

The adjusters need to be turned in the direction of the rotation of the wheel, looking at it from when you are laying underneath, so that means all but the drivers front wheel adjuster will be turning clockwise while it goes anti-clockwise. And don't forget the ones behind the steering arms on the front.

Now press the pedal a couple of times to move some more fluid around but then rest for a few seconds and try again and you should get almost no movement of the pedal, other than taking up the slack in the pins and pedal. Hold the pedal and if it sinks you have a leak, spongy you have air or a decent amount of travel you have something else wrong.

Terry
 

[Mokee Moke]

   As a simple question, when you say you rebuilt the whole brake system on your moke did you fit the rear brake proporsioing valve back into the system?  You say the pedal nearly goes to the floor but you can pump it up. Maybe it’s not holding the brake line pressure as it should?  Other members may have more corrective measures if this is the problem.

Hello YT, I removed the brake proportioning valve, stripped and cleaned it, then refitted it. It was full of gunge. Once cleaned, the ball moved freely. As per another member's advice, I made sure the car was level on jack stands so the ball was in the correct position. I was concerned it may be a good trap for air, so I bled the valve first, then bled the rear wheel cylinders. So I believe the valve is functional and free of air.

[Mokee Moke]

Hi Mokee,

Being able to pump up the brakes to get a better pedal is usually a sign of bad adjustment. Air in the system would give a spongy pedal.

With the rear, did you adjust them with the handbrake cable disconnected? Turn the adjuster until the brakes are locked hard and then back off until the wheel turns freely. Then adjust the cables until you can drop the pin back in at the wheel.

With everything being new I reckon you will have a bit more pedal travel until it all beds in, but it should be consistent and shouldn't go near the floor.

Cheers, MD.

Thanks MD. I did the adjustment on the rear brake shoes without the handbrake pin in the expander lever, pretty well as you described. But I didn't do the handbrake cable reconnection as you have described (I followed the manual's method), so I will give your handbrake adjustment tip a go.

[Mokee Moke]

Hi,

another diagnostic step is to adjust up all for wheels so that they are locked up tight without your foot on the pedal at all. A good way to do this is to have someone hold the pedal down and while you go around and adjust everything up tight.

The adjusters need to be turned in the direction of the rotation of the wheel, looking at it from when you are laying underneath, so that means all but the drivers front wheel adjuster will be turning clockwise while it goes anti-clockwise. And don't forget the ones behind the steering arms on the front.

Now press the pedal a couple of times to move some more fluid around but then rest for a few seconds and try again and you should get almost no movement of the pedal, other than taking up the slack in the pins and pedal. Hold the pedal and if it sinks you have a leak, spongy you have air or a decent amount of travel you have something else wrong.

Terry
 

Hi Terry, I will give your method a go later today (I need to get SWMBO interested in assisting )and get back to you.

[Mokee Moke]

Thanks guys for your support. Mokee is proving to a problem child at the moment

[Mokee Moke]

Ok. So here's the latest update.

First up, I disconnected the handbrake cables from the rear brake levers (note, pins were already a loose fit as per YT's response above)
Then I re-checked rear brake shoe/drum tension as per Terry's method. Drum was locked if I rotated adjuster one 'click', then free if I back it off one click.
Next, I clamped both front brake hoses to isolate the front discs.
Result: rock hard pedal!
Conclusion: rear brakes are good; front callipers or master cylinder at fault.

I then removed one clamp from a front disc hose, and re-checked pedal.
Pedal now travels half way to floor.
Next I removed the other clamp (i.e., both clamps removed) and re-checked pedal.
Result: pedal is nearly at floor when applied.

I had SWMBO apply the brakes whilst I observed the disc/pad interaction. I could see a fraction of movement of the pads, which seems right.
Conclusion: front callipers are good; master cylinder at fault?

The master cylinder is brand new (as is nearly everything else!), which is a new type tandem variety; see following photo. The top line goes to the front brakes via a T-Union mounted on the firewall. The bottom line goes to the rear drums via a brake compensator mounted on the rear chassis rail.

Note: I still can't work out why the handbrake won't work either

Cheers, Greg

[Mokee Moke]

\

[Drakman]

Hi Mokee,

For my 2 cents worth i would jack the back up, take the drums off and watch the hand brake rod action to make sure the hand brake rod is in the right slots in the shoes and is doing it's bit by moving the shoes out.  How far up does your handbrake lever, the one in the car, move when you apply the hand brake?

For your fronts i have one of those cheap plastic hand pump type vacuum brake bleeders and it works a treat, one person job and just keep recycling the brake fluid as it drops into the catch bottle until you're happy with the pedal travel and feel.

Cheers
Dave