Thread: spongey brakes

Originally Posted by willvine

Hey guys and girls,

After a few arvos trying to get a good pedal, bleeding the brakes on my 109 series 3. I bit the bullit and took it to the brake shop. They had it sorted in 10 minites but said that i could have the wrong backing plate???? and that the bleed nipple should be on the top of a duel wheel cylender type brake system.

My bleed nipple is on the bottom on the front backing plate is this correct?.

They said as air rises. the bleed nipple needs to be on the top wheel cylender to let it out other wise it will circulate in the top cylender.

can any one confirm this as I was sure that the bleed nipple was on the bottom on a 109 series 3.

Thanks
Will.

The brake hose goes to the top cylinder, to keep it out of the way of danger as far as possible and to keep the hose short. The bleed valve MUST be on the furthest cylinder from the master cylinder. So yes, the bleeder MUST be on the bottom wheel cylinder.

This does make bleeding these brakes difficult, because, as your brake shop says, air rises, although there is no way it is going to rise up the connecting pipe while you are bleeding. The main problem is usually air pockets in the actual cylinders. This can usually be removed by backing adjusters right off to minimise the volume in each cylinder, and clamping the other hoses so you can get maximum fluid flow at the wheel you are working on to drag the air out with it. If it is a dual system it makes it even harder. It is sometimes necessary to bleed at each end of the connecting pipe as well as the bleed nipple.

John

I have experienced this problem before aswell. Do as suggested before. Back the adjusters right off, and bleed first by backing off the steel line. Try using the "finger to make a one way valve over the slackened bleed nipple" method. This lets you bleed it a bit quicker to force the air through.
Aaron.

Yes there can be problems with the backing plate but more often it is with incorrect shoes or not putting them on properly. Leading and trailing shoes have the post that the snail cams adjust in different positions, so if you put in a trailing shoe as a leading shoe there will be issues - how do I know - I just installed the shoes the wrong way around on my truck and installed everything before I realised what I had done.

Yes - and against logic - the bleed screw is on the bottom of the front brakes - if anyone tells you it should be at the top they do not know landies very well. If you keep on pumping with the required pause between each pump they will bleed it just takes a bit of fluid - how do I know - just been through this process as well.

There is a mod that brings in the brake fluid at the bottom cylinder rather than the top so the bleed screw can go in the top but it is a mod and not really worth the hassle.

Garry

Garry

The other guys have pretty much covered everything.

The only thing I will add is that sometimes it is impossible to get ALL the air out, but you can remove enough to get brakes that are more than sufficient. Over a few days, the system (IME) tends to self-bleed the last tiny bit of air. I assume it works its way to the MC.

Adjustment is very critical, since there are 6 adjusters on a 109". Which reminds me, I need to adjust mine!