Auto Reverse not working - Page 7

Sargan · 19 June 2018, 23:12

Quote:

Originally Posted by charliee

i'm sure that a light weight Alko head. this must be driving you made - I would consider changing the hubs on the basis they may be too worn.

You can't, unless you mean the drums ..... the hubs are welded on stub axles & backplates - would need to change whole axle.

Sargan · 20 June 2018, 12:34

Quote:

Originally Posted by G4b3 nixon

I couldn't open the image, but does it have a slot on the top like the knott head in the photo attached. I have pictured the open slot and the lock out available. Also an older type that i have that would be the easiest to fabricate although it would mean removing the gaiter.

The forum will not let me post an image what I posted was a link to the image - now managed top get picture by fully embedding with HTML.

There is no 'catch'

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20180616_135231 by argonanut, on Flickr[/IMG]

paintman · 20 June 2018, 20:22

The catch referred to is for particular Knott couplings.
Page 50 in this link, item 22:
https://www.barlowtrailers.co.uk/ima...-couplings.pdf
Manual Reverse Kit. While the basic reversing function remains
automatic, this kit allows easier reversing up steep hills or on poor
surfaces, where traction can sometimes be a problem. Please note Can
only be fitted to the KFG27 coupling manufactured from late 2005 that
has slot fitted as standard.

See also Page 51.

Would suggest that Knott are aware of an issue.

Sargan · 20 June 2018, 20:33

Quote:

Originally Posted by paintman

Would suggest that Knott are aware of an issue.

Maybe endemic in autoreverse mechanisms.

Most boat owners I know remove brakes entirely because they have corroded up.

My plan now seems to be ... I will cross drill the coupling to facilitate insertion of a 10mm round bar ... such that the 'pawl' cannot move backwards, and thus brakes can't operate.

G4b3 nixon · 20 June 2018, 21:04

Quote:

Originally Posted by Sargan

Maybe endemic in autoreverse mechanisms.

Most boat owners I know remove brakes entirely because they have corroded up.

My plan now seems to be ... I will cross drill the coupling to facilitate insertion of a 10mm round bar ... such that the 'pawl' cannot move backwards, and thus brakes can't operate.

Agree entirely, i have just stripped the brakes out of an old trailer to reduce any issues, however i tow with either an isuzu dmax or a van so know I have plenty of stopping power in front of any trailer.

I think your idea is the simplest solution. I haven't tried it myself, have you checked that there is no issue with broaching this section by drilling? This may be a stupid point as i am not familiar with this head,but I assume you are not going to leak fluid by drilling this?

Sargan · 20 June 2018, 21:19

Quote:

Originally Posted by G4b3 nixon

I haven't tried it myself, have you checked that there is no issue with broaching this section by drilling? This may be a stupid point as i am not familiar with this head,but I assume you are not going to leak fluid by drilling this?

I am drilling below the damper to avoid that ... so just into the pressed steel section ... and bar will then be just behind the actuator pawl

Orwell boy · 20 June 2018, 21:25

Quote:

Originally Posted by G4b3 nixon

Agree entirely, i have just stripped the brakes out of an old trailer to reduce any issues, however i tow with either an isuzu dmax or a van so know I have plenty of stopping power in front of any trailer.

I think your idea is the simplest solution. I haven't tried it myself, have you checked that there is no issue with broaching this section by drilling? This may be a stupid point as i am not familiar with this head,but I assume you are not going to leak fluid by drilling this?

Stupid move for road use ,dont matter how much stopping power you have ,if your over 750Kg ,not braked and you run out of control and kill a child you will hang ....simple get it right or don,t go on the road

willk · 20 June 2018, 21:50

Quote:

Originally Posted by G4b3 nixon

Agree entirely, i have just stripped the brakes out of an old trailer to reduce any issues, however i tow with either an isuzu dmax or a van so know I have plenty of stopping power in front of any trailer.

Damn those pesky brakes! Can't believe I service mine annually when I could just bin them. My D-Max is gonna love the new regime

paintman · 21 June 2018, 08:58

If the weight is below 750kg then you don't need brakes at all, just a means of stopping the trailer proceeding independently if it breaks away.
Over 750kg you need brakes. If you choose to run without then you take the risk of being hung out to dry if you have an accident. Your insurers will likely pay out to any third party but may then come after you for the money.
If pulled by Police/DVSA, weighed & the trailer is not compliant you will be issued a PG9 Prohibition notice - a Police issued one is immediate - & will then need to arrange a full lift recovery of the trailer.

I weighed mine some years ago fully loaded at the local weighbridge & carry the certificate in the car.

charliee · 21 June 2018, 09:20

I'd be concerned that removing C. 15% of the tube by drilling 2 x 10mm holes may significantly weaken the tube, I'd be inclined to drill a much small hole and use a smaller rod to block the compression function.

On suggestions of removing brakes this is utterly daft unless the trailer never ventures onto a public roads or is towed by a tractor (unless under 750Kgs). The cost of an annual service to keep a trailer together is nothing compared to the ramifications in case of an accident.

Sargan · 21 June 2018, 11:16

I am not going to drill the tube at all.
I am going to drill an 8 or 10mm hole so that I can insert a rod just behind the brake actuating lever .... so that when tube presses on lever it can't go anywhere.
So no weakening of tube involved.

G4b3 nixon · 22 June 2018, 18:48

Quote:

Originally Posted by Orwell boy

Stupid move for road use ,dont matter how much stopping power you have ,if your over 750Kg ,not braked and you run out of control and kill a child you will hang ....simple get it right or don,t go on the road

Chill out angry people. I have never removed brakes on a trailer over 750kg gross. You didn't stop to ask. I have owned braked trailers that i have used for towing lighter boats than designed for. And before anyone points it out it didn't have a plate.

Before you get preachy consider my 3.5t dmax stopping a 750kg trailer and a family car trying to do the same thing and then consider who is most likely to 'kill a child'

69cmw · 22 June 2018, 19:04

Quote:

Originally Posted by paintman

If the weight is below 750kg then you don't need brakes at all

That’s utter bull.
If you look not all cars can tow 750kg unbraked .... some are less

Poly · 22 June 2018, 21:10

Quote:

Originally Posted by paintman

If pulled by Police/DVSA, weighed & the trailer is not compliant you will be issued a PG9 Prohibition notice - a Police issued one is immediate - & will then need to arrange a full lift recovery of the trailer.

DVSA enforcement is immediate too - although they tend to focus on commercial vehicles.

Don’t forget that they will also almost certainly prosecute you for either driving an overloaded vehicle (if plated for 750kg and carrying more) or driving a vehicle in a dangerous condition (if plated correctly and brakes removed). In fact, I’d be surprised if they were happy with a high plated trailer with no brakes even if it happened to be under 750kg at the time of the stop.

Sargan · 23 June 2018, 21:50

OK ..... I gave up trying to fix this, had dozens of people provide suggestions. Replaced loads of spare parts, taken it into Indespension twice - still unresolved.

Instead I modified the Coupling so that the 'Brake actuating lever cannot move' i.e. the hydraulic coupling cannot move backwards.
I did this without touching the sliding tube, damper or seals.
Instead I drilled the frame such that a 12mm high tensile pin can be inserted immediately behind the 'S Pawl' (Brake actuating lever).

The white on pin is just primer I was pushing into the hole .... the red band is to make sure it goes in for correct insertion depth.
Not a through hole ... though both walls of the square section and 3/4 through the handbrake assembly plate .... dicn't make it through hole as it would go though the swivel part of handbrake assembly, and was too close to grease nipple.

Insert pin for reversing up hill, out and brakes function as normal.

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P1000415 by argonanut, on Flickr[/IMG]

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P1000419 by argonanut, on Flickr[/IMG]

paintman · 24 June 2018, 00:59

Quote:

Originally Posted by Poly

DVSA enforcement is immediate too - although they tend to focus on commercial vehicles.

Don’t forget that they will also almost certainly prosecute you for either driving an overloaded vehicle (if plated for 750kg and carrying more) or driving a vehicle in a dangerous condition (if plated correctly and brakes removed). In fact, I’d be surprised if they were happy with a high plated trailer with no brakes even if it happened to be under 750kg at the time of the stop.

DVSA operatives have the option to issue a delayed PG9.

paintman · 24 June 2018, 01:09

Quote:

Originally Posted by 69cmw

That’s utter bull.
If you look not all cars can tow 750kg unbraked .... some are less

There are cars that can't tow anything!
However:
A trailer with a GVW of 750kg or lower, is not required to have brakes, but if brakes are fitted they must be in full working order.

https://www.gov.uk/government/public...van-the-basics

That said you make the valid point that you should always check what the plate on your car says in respect of what it can tow before hitching up your new trailer & heading off into the sunset as the max weight on many is surprisingly low.

Jeff · 10 July 2018, 14:51

Did you ever get to the bottom of the problem? It could help others in the future [emoji106]

Sargan · 10 July 2018, 15:56

Nope .... Trailer manufacturer could not fix it ... 2 different specialists .... no change.

I carried out my workaround in:
http://www.rib.net/forum/f49/auto-re...tml#post774773

and now accept that is what it is.

Sargan · 10 July 2018, 20:44

My considered assumption is the following:
If brakes are applied, when drums rotate backwards, it allows shoe to swivel the cam against the spring pressure and this trips the shoe away from drum and the other shoe releases due to imbalance.

I think the design relies on this ‘trip’ happening based on an expected range of movement .... as trailer ages ... the drums wear (estimate about 4mm off thickness .. therefore 8mm larger diameter) meaning shoes to travel further to ‘brake’
You adjust brakes shoe gaps ... but they will operate at different bearing angle on cam.
My assumption is if all is new the shoes start to touch drum before full braking rod pressure, and the shoes can then trip.

Due to extra travel the angle of the cams is changed and the brakes lock tight before they get to an angle that allows them to trip

Only way to prove it would be to swap axles .... way too expensive.