Transmission Brake Issues

Hello,
Bought a 1983 series 3 the other day to use as a towing/launching vehicle at our boat yard. I need the hand brake to work well, so I can stop on the slipway with 3 tonnes of boat on the back and be confident of not killing anyone.
For her age, the drum and pads look in reasonable condition. When I tool the drum off, no sign of any oil anywhere, apart from, weirdly, on the metal part of the TOP brake shoe. I cleaned this off, and it has not reappeared.
I ordered and fitted new shoes anyway, as I read they were a cow to clean if contaminated with oil. The inside of the drum is almost shiny smooth, I tried roughening it with 80G sandpaper, but without taking off the prop shaft its hard to do a decent job of this by hand under the old girl. But it is clean, and not grooved.
When fitting the new shoes today I checked the expander mechanism and it seemed to give a very small movement to the shoes. The expander "pistons" only move out about 0.5mm when manually pulling the rod that the bell crank is attached to (with handbrake lever disconnected) the full distance of travel. Does this sound correct? It seems a very small amount.
When re fitting everything, I made sure the rod linkage length was enough to let the expander back in fully, and I tightened the adjuster until it was just biting, then backed off a "click". I applied and re applied the brake to settle and square the shoes, and repeated the adjuster setting. There is plenty of movement left in the lever, and the bell crank is miles away from hitting the chassis/transfer box thingy.
All to no avail. The only way I can get her to hold her own weight on even a moderate slope (let alone with a trailer) is by over tightening the adjuster, so that it is biting quite hard when the brake is off. She then holds, just, but you can feel the resistance when driving, and the drum feels warm after about 20 ft.
I have heard the brake is supposed to be very good, if properly adjusted. Any ideas what might be my issue? Could the expander be at fault as 0.5mm or so doesnt sound like enough movement to me.
Am thinking I might have to cut a hole between the seats and stick a large screwdriver into the UJ at the front of the propshaft, might be simpler....
Any help much appreciated, but bear with me, I am new to this maintenance malarkey, and new to being a Landy owner too...

expander needs looking at easy enough to get wrong

It’s easy to get the wedges in wrong number 26 on diagram one goes out and one goes in when you pull on handbrake
You can download full manual on retroanaconda site and parts book
welcome to club
More adjustment in handbrake lever too shouldn’t need. Ascrwdriver

You must have the odd anchor knocking around.

As above. Looks like the adjuster needs a fettle.

Having done the done the heavy boat launch many times here are some tip's for when you get the hand brake working correctly.
First I think 3 tons is a lot to hold on anything other than a shallow ramp. I felt two ton boats were enough for the slip I used
When reversing use low range for more control, this also means the handbrake also works on the front wheels.
When in position on the slip before getting out to prepare for launch have your assistant put the brake on the trailer and chock the wheels, If leaving the truck switch off with it in first low hand brake on. Make sure ratchet is in good order.
I would then disconnect the Trailer and then move the landy forward to take the strain on a strop already connected between them.
When the load was taken up assistant would remove the chocks and release the trailer brake and step out of the way to keep an eye on stuff and others out of the way. Trailer then let down into the water without the landy going in. Take care.

Take your time setting up the linkeage too so all the angles are just coming up to 90 deg when its on full. People tend to adjust the link that's easiest to get to so it can get all out of position. What diffs do you have? My LWB has 3.54 and these really cut down the transmission brake effectiveness. Also do you have TLS fronts? These don't hold on a hill (backwards).

rob1miles said:

. Also do you have TLS fronts? These don't hold on a hill (backwards).

Click to expand...

I know you know the brake shoes on any of the wheels don’t move when you pull on the transmission brake!

Ha, my point (badly put) was that if the trans brake is weak you want to be facing down the hill so you can stamp on the brakes, if you are facing up there's really only the rear drums doing anything. Its a very good argument for discs.

Mine has the shoes fitted that it came out of the factory with...over the years they have been wet with oil....still holds well.
Modern shoes just don't seem to fit were they should to me...can be a nightmare....

Handbrake on....in first gear....chock wheel if ness.

Thanks for all your help. The problem was a toppled over roller in the expander unit, meaning the shoes didnt travel enough when the brake was applied.
After fixing it and making sure its all adjusted right, it holds brilliantly. Am fitting a front hitch so I will be driving forward down the ramp, so the foot brake should work better too.

Low range or 4x4 selected, other wise it can slide off even with handbrake on.

Agree with comment ref oil on shoes, mine were always wet! and on the way for its mot I would lightly apply the handbrake for the last mile to two to burn some crap off, always worked well for quite some time afterwards.

In the end I fitted a speedisleeve to stop the oil leaks, and ot has been dry for a few years now.