Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc. Adjust brakes
The reverse override link & spring are not removed during service (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
..... so only a problem when push rod activates.

Any suggestions ?

rick wrote:

Have a twin axle trailer.

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

AIUI, in reverse when the shoes touch the drum they move and are
then retracted from the drum, it would seem that this mechanism
is for some reason not working.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

Chris J Dixon explained on 07/05/2018 :
AIUI, in reverse when the shoes touch the drum they move and are
then retracted from the drum, it would seem that this mechanism
is for some reason not working.

They use the fact that the overun brake is under compression and the
wheels are attempting to be be turned backward, to disengage the brake
shoes.

If the overrun brake is under compression, but the wheels are rotating
in the forward direction, then the brake shoes will work normally.

There is a full explanation here..

http://www.al-ko.co.uk/edit/files/ha...m-handbook.pdf

On Monday, 7 May 2018 08:39:37 UTC+1, rick wrote:
Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc. Adjust brakes
The reverse override link & spring are not removed during service (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

Any suggestions ?

It's been a while so others may be more up to date or complete on this. Overrun brakes will do that if the spring stopping them acting is too weak, or if the car is jerked backward.


NT

But on all 4 wheels at same time points to a common fault not on a hub
issue (at least I think)

On 07/05/2018 08:51, Chris J Dixon wrote:
rick wrote:

Have a twin axle trailer.

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

AIUI, in reverse when the shoes touch the drum they move and are
then retracted from the drum, it would seem that this mechanism
is for some reason not working.

Chris

On 07/05/2018 10:25, wrote:
On Monday, 7 May 2018 08:39:37 UTC+1, rick wrote:
Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc. Adjust brakes
The reverse override link & spring are not removed during service (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

Any suggestions ?

It's been a while so others may be more up to date or complete on this. Overrun brakes will do that if the spring stopping them acting is too weak, or if the car is jerked backward.


NT



All 4 hubs are locking on ... so unlikely all 4 springs went weak at
same time ..... must be something common, I'll try resetting actuating rod.

On Monday, 7 May 2018 14:46:14 UTC+1, rick wrote:
On 07/05/2018 10:25, tabbypurr wrote:
On Monday, 7 May 2018 08:39:37 UTC+1, rick wrote:

Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc. Adjust brakes
The reverse override link & spring are not removed during service (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

Any suggestions ?

It's been a while so others may be more up to date or complete on this. Overrun brakes will do that if the spring stopping them acting is too weak, or if the car is jerked backward.


NT



All 4 hubs are locking on ... so unlikely all 4 springs went weak at
same time ..... must be something common, I'll try resetting actuating rod.

last one I played with had 1 spring pushing the drawbar out, but it was a long time ago.


NT

Update on this ...
Replaced the actuation rods,as the adjuster was corroded solid.

Set that up so correct clearances .... again brakes activating fine,
handbrake holding fine - and in correct 90 degree position.

However auto-reverse still not working.

Anybody any clues.

On 07/05/2018 08:39, rick wrote:
Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc.Â* Adjust brakes
The reverse override link & spring are not removed during serviceÂ* (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

Any suggestions ?

On Friday, 11 May 2018 16:06:51 UTC+1, rick wrote:
Update on this ...
Replaced the actuation rods,as the adjuster was corroded solid.

Set that up so correct clearances .... again brakes activating fine,
handbrake holding fine - and in correct 90 degree position.

However auto-reverse still not working.

Anybody any clues.

On 07/05/2018 08:39, rick wrote:
Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals, clean
drums etc.Â* Adjust brakes
The reverse override link & spring are not removed during serviceÂ* (AlKo
instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper completes
travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no issue
.... so only a problem when push rod activates.

Any suggestions ?

show us a pic/diag of the mechanism


NT

On 07/05/2018 08:39, rick wrote:
Have a twin axle trailer.
Each year service hubs ... wash out all grease, repack, new seals,
clean drums etc.Â* Adjust brakes
The reverse override link & spring are not removed during service
(AlKo instructions)

The brakes are AlKo auto reverse type.
Going fwd brakes work fine, stationary handbrakes applies and holds.

In reverse after a short distance (presume until hitch damper
completes travel) the brakes lock on.
If I unhook trailer and manoeuvre by hand it will reverse with no
issue .... so only a problem when push rod activates.

Any suggestions ?


I have not seen most of the replies, so I'm probably repeating some of them!

I'm assuming they are the same type as the Alko caravan brakes.

The brakes are supposed to initially lock-on after the damper/push rod
is pushed in as this causes the trailer brakes to operate under normal
braking conditions. However, when reversing, the brake shoes lock but
then are partially released by the action of the brake drum assembly
rotating.

For this to happen correctly the brake shoes and the push rod
adjustments are critical.

We have a small caravan and there are times when it seems as if the
brakes aren't going to release when starting to reverse onto a pitch.

Sam

On 11/05/2018 17:17, wrote:


show us a pic/diag of the mechanism

It's as per the link posted by Harry

On 11/05/2018 17:53, Sam wrote:


For this to happen correctly the brake shoes and the push rod
adjustments are critical.



Decide to replace all 4 Bowden cables, lubricate the expander mechanisms
and set up again as per manual.

Strange getting conflicting advice .... phoned 2 different Indespension
dealers
1 said brakes must be too tight, need to be slack so they don't bind too
early ion reverse.
The other said they must be only just backed off from 'locked' (i.e.
much tighter then normal) as they need to lock solid as soon as drum
starts reversing to force auto-reverse release to operate.

On 21/05/2018 22:59, rick wrote:
On 11/05/2018 17:53, Sam wrote:


For this to happen correctly the brake shoes and the push rod
adjustments are critical.



Decide to replace all 4 Bowden cables, lubricate the expander mechanisms
and set up again as per manual.

Strange getting conflicting advice .... phoned 2 different Indespension
dealers
1 said brakes must be too tight, need to be slack so they don't bind too
early ion reverse.
The other said they must be only just backed off from 'locked'Â* (i.e.
much tighter then normal) as they need to lock solid as soon as drum
starts reversing to force auto-reverse release to operate.


Replaced all 4 cables ... checked adjustment again ... and still locks
on when reversing up hill.

On Monday, 28 May 2018 00:31:50 UTC+1, rick wrote:
On 21/05/2018 22:59, rick wrote:
On 11/05/2018 17:53, Sam wrote:


For this to happen correctly the brake shoes and the push rod
adjustments are critical.



Decide to replace all 4 Bowden cables, lubricate the expander mechanisms
and set up again as per manual.

Strange getting conflicting advice .... phoned 2 different Indespension
dealers
1 said brakes must be too tight, need to be slack so they don't bind too
early ion reverse.
The other said they must be only just backed off from 'locked'Â* (i..e.
much tighter then normal) as they need to lock solid as soon as drum
starts reversing to force auto-reverse release to operate.


Replaced all 4 cables ... checked adjustment again ... and still locks
on when reversing up hill.

I looked at the reverse unlocking mechanis but didni't understand it. Do you?


NT

rick wrote:
On 21/05/2018 22:59, rick wrote:
On 11/05/2018 17:53, Sam wrote:


For this to happen correctly the brake shoes and the push rod
adjustments are critical.



Decide to replace all 4 Bowden cables, lubricate the expander mechanisms
and set up again as per manual.

Strange getting conflicting advice .... phoned 2 different Indespension
dealers
1 said brakes must be too tight, need to be slack so they don't bind too
early ion reverse.
The other said they must be only just backed off from 'locked'Â* (i.e.
much tighter then normal) as they need to lock solid as soon as drum
starts reversing to force auto-reverse release to operate.


Replaced all 4 cables ... checked adjustment again ... and still locks
on when reversing up hill.


This any help? https://youtu.be/PLivXJiGkMA

I must admit the Alko diagrams are a bit rubbish at illustrating what
actually goes on and the video perhaps doesnt add much.

Tim

--
Please don't feed the trolls