Thread: Brakes, very wooden - servo not working?

To test the servo - with the engine off pump the brakes a few times - this removes any remaining vacuum in the servo.

Then with your foot firmly on the brakes (but not necessarily hard down) start the engine and the brake pedal should then go down further. By pushing the pedal down before start you are doing this with no vacuum assist. When you start the engine the vaccum reduces the amount of pressure required and as you cannot counter quickly enough your foot pushes the pedal down. If there is no vacuum or the servo diaphragm is perished there is no suction so the pedal does not go down any further on startup.

Garry

Ahh easy to test, just what I hoped for.

Cheers!

If you find that your servo is not working, before assuming the problem is the servo, check the tubing for leaks, typically a split where it goes onto a fitting.

John

OK so I did the test that garrycol suggested, when starting the motor the pedal does depress a little more but not much and very slowly.

I had a quick look at the hoses and couldn't see any splits, I will go over them more carefully this afternoon.

I have also noticed that the front left wheel always locks up first under even moderate braking - what is the most likely cause of the imbalance?
It is quite dangerous because the car wants to spear left under brakes!

Originally Posted by ashhhhh

I have also noticed that the front left wheel always locks up first under even moderate braking - what is the most likely cause of the imbalance?
It is quite dangerous because the car wants to spear left under brakes!

Assuming no other issues - the drum brakes on series landies require manual adjustment and need regular attention. Most drum landies I have driven pull one way or the other if it has been a while since they have been adjusted.

Try adjustment first and if no luck the you will need to look further.

Garry

Originally Posted by ashhhhh

.......
I have also noticed that the front left wheel always locks up first under even moderate braking - what is the most likely cause of the imbalance?
It is quite dangerous because the car wants to spear left under brakes!

This is almost certainly due to oil contamination of the LH front brake from a leaking hub seal. It should be dealt with ASAP. However, you should not miss the possibility that both this and the "wooden" brakes are due to the RH front brake not working at all, or very little, due to a seized wheel cylinder or blocked hose.

Series drum brakes should not pull to the side, and if they do it will usually be due to contamination of the linings or very bad adjustment. (Or a soft front tyre!)

John

Well I adjusted the brakes this arvo and things do feel a fair bit better.
It doesn't veer left anymore at least and it feel much safer.

A couple of things though;

The pedal is very high and has little travel, better than being spongy but it seems to reduce the amount of leverage you can get.
Is there a way to adjust this?

The rear right wheel was a little greasy inside the drum.
I cleaned it all down and will keep a eye on it, I assume its an axle seal if it keeps greasing up?
Also, one of the drum adjusters on this wheel just turns endlessly.
It does not tighten up.
Does this mean something is stripped or that the shoe is worn outside its limit?
It seemed to have at least as much meat as the other corners.

Cheers,
Ash

Originally Posted by ashhhhh

Well I adjusted the brakes this arvo and things do feel a fair bit better.
It doesn't veer left anymore at least and it feel much safer.

A couple of things though;

The pedal is very high and has little travel, better than being spongy but it seems to reduce the amount of leverage you can get.
Is there a way to adjust this?

Probably indicates you have them adjusted up to the extent they are dragging. And changing the pedal travel will not change your leverage. Only thing is to ensure there is a small amount of free play to allow the M/C piston to come right back.

The rear right wheel was a little greasy inside the drum.
I cleaned it all down and will keep a eye on it, I assume its an axle seal if it keeps greasing up?

Hub seal. If the brake shoes were greasy, they probably need replacing.

Also, one of the drum adjusters on this wheel just turns endlessly.
It does not tighten up.
Does this mean something is stripped or that the shoe is worn outside its limit?
It seemed to have at least as much meat as the other corners.

Could be the adjuster worn, possibly the peg on the shoe worn (or even missing) , but is most likely a combination of worn lining and worn drum.

Cheers,
Ash

Have you got the booster working any better?

John