Brake Adjustment

[T34]

I've purchased my trusty Haynes manual so no problems on actually adjusting the brakes, but wanted to ask for others hints / tips - ie what to be aware of / look out for on a 35 year old braking system.

Thanks in advance.

Mick.

[T34]

Actually - should probably be a bit more specific and say '35 year old Land Rover brakes' (had plenty of experience with classic cars in general).

[JDNSW]

It will depend to some extent on whether it has dual circuit of single circuit hydraulics - the single circuit seem to give less trouble with bleeding.

Assuming that the braking system is in good condition, there should be no problems in adjusting the brakes. However, satisfactory adjustment will not be possible if there is any air in the system.

If there are problems bleeding the system try clamping off all three hoses, and release one at a time to confirm there is no spring left in the pedal (with hoses clamped there should be a completely solid pedal. Do not be afraid to bleed at all joints if necessary as well as the bleeders. Best results will be obtained if the brake adjusters are right off when bleeding, to minimise the space in the cylinders.
Having said this, though, I have never had any problems bleeding these brakes.

When adjusting them, watch for the possibility that the adjusters are either seized, have the serrations worn off, or the snails are loose on the shaft. In any of these cases, adjustment is impossible. You can get new adjusters.

As usual, excessively worn drums or linings will prevent adjustment, as will seized wheel cylinders or contaminated linings. If you have any doubts at all, I would be inclined to jack up all four corners and remove the drums for inspection before starting, and replace wheel cylinders, linings etc as needed. As well as inspecting the master cylinder and plumbing for leaks.

In my experience, these brakes are quite easy to work on and work well if all bits are in good shape. Adjustment is needed however at every service, which comes as a bit of a surprise to anyone used to self adjusting discs!

John

[T34]

The pedal feels solid but the travel is long - seems like maladjusted / worn shoes - it pulls up pretty straight too.

An inspection sounds a good idea - at least it will put my mind at ease if nothing else.

[JDNSW]

The pedal feels solid but the travel is long - seems like maladjusted / worn shoes - it pulls up pretty straight too.

An inspection sounds a good idea - at least it will put my mind at ease if nothing else.

Sounds like the brakes are good - as you say, that sounds like they just need adjusting; as I said, you need to adjust them every service. But pulling the drums off to have a look is worth doing if you are new to the vehicle to check the state of the shoes and drums and make sure all the adjusters work properly.

It is possible, but unlikely that the free play on the pedal push rod is too great, but this is easy to check (I have known the lock nut to come loose).

John

[T34]

Cheers, Good tip - I will check this out too.

[__Will__]

While we're on the topic of series III brakes, I'll just throw a question in here too :)

Does anyone know what the thickness of a new brake lining is? I've checked the linings on the two front brakes and they seem to be fine (still about 5mm left). But when I try to tension them out using the adjuster bolt to maximum, they are still moveable by hand. So to me this spells either a) the linings are quite worn (which seems strange as there are no rivets visible and I would have thought 5mm is sufficient for the time being) or b) the drums have worn a hell of a lot :mad:

There are no signs of any fluid intrusion either, and I blew a load of compressed air in them as there was a LOT of dust in there. I was told when I bought the vehicle that it hadn't seen a lot of action for many years, so can they deteriorate with time/lack of use to a certain degree?

Cheers, Will

[dandlandyman]

The linings should at least be as thick as the metal of the shoe, though the brakes will work and be adjustable until worn right down to the metal. Perhaps your drums are worn out, or maybe machined out. I had a drum on my Forward Control which was so worn that when I hit it firmly with a hammer to get it off the thing actually dented! Useless even before I got to it, only good for a paperweight (and conversation point) now.

Dan.
69 2a 88" pet4, 74 3 109" pet4, 68 2b FC pet6.

[Olive Drab]

I've had a couple of landy's and no two systems ever seem to bleed the same. One I had took a few pumps of the pedal crack the nipple and all done. The one I have now didn't want to play the game at all. So the dont argue method was used the "air bleeder" one lap round the car all done.
Back to the other landy, I decided to treat the brakes as I would a truck braking system, all drums and shoes off and down to the brake shop to have the shoes radius ground. It is important to keep all the shoes and drums as a matched set at each corner when doing this. The added cost is well worth it I reckon 20-30% better performance from the non boosted brake system.
If anyone wants to borrow the air bleeder let me know.

[JDNSW]

While we're on the topic of series III brakes, I'll just throw a question in here too :)

Does anyone know what the thickness of a new brake lining is? I've checked the linings on the two front brakes and they seem to be fine (still about 5mm left). But when I try to tension them out using the adjuster bolt to maximum, they are still moveable by hand. So to me this spells either a) the linings are quite worn (which seems strange as there are no rivets visible and I would have thought 5mm is sufficient for the time being) or b) the drums have worn a hell of a lot :mad:

There are no signs of any fluid intrusion either, and I blew a load of compressed air in them as there was a LOT of dust in there. I was told when I bought the vehicle that it hadn't seen a lot of action for many years, so can they deteriorate with time/lack of use to a certain degree?

Cheers, Will

The adjusters should be able to get the brakes to work with the metal touching the drums! Several possibilities:-

1. Adjuster or the peg they bear on worn excessively, or adjuster loose on pivot. (or all the serrations worn off and it is not staying where you put it!)

2. Drum is oversize due to wear, machining or both. Maximum oversize is 0.75mm, standard size is 10" or 11" exactly.

3. (unlikely) heel of shoes or anchor point is worn.

I would not under any circumstances use compressed air to remove brake dust. If the linings have not been replaced for many years it almost certainly has asbestos linings, and using compressed air not only gives you a good chance of breathing the stuff, but is likely to spread it all over the workshop to make sure everone else who comes in for the next six months does as well. Even if the current linings do not contain asbestos, it certainly had them in the past, and there is likely to be some of that left.


John

[T34]

Mnn asbestos - nasty stuff.

On the subject of air bleeders - I went to purchase one of these when doing the brakes on another project but they seemed very expensive for what amounted to a plastic bottle with an airline (yours may be different) - the ones I saw were certainly not 180 dollars worth!!

In the end I found a hand operated vacuum brake bleeder - obviously a little more effort than the air powered version, but it does come with a a vacuum gauge and can also be used for testing things such as the vacuum advance on the distributor - I paid about 70 bucks for it - well worth it in my books - also you can instantly see if you have problems such as swollen / restrictive hoses as the vacuum gauge goes off the scale and no brake fluid comes through.

[JDNSW]

And yet another method is to reverse bleed. I have never used this on brakes, but have on the 110 clutch when it was immobile on a downhill slope. Simply a syringe as used for filling diffs etc, but filled with brake fluid (if it is one you have used for that be very sure it is scrupulously clean first, degreased, washed, flushed with metho - better to use a new one).

John