Sankey trailer brakes

[Tinbasherdan]

I’ve acquired a narrow track sankey chassis to convert into a camping pod, the issue being is that the original drum brakes have been removed. I’ve also acquired a complete hydraulic brake drawbar from a mk3 disk brakes wide track. Anyone any experience with converting the drum setup to disk? Surely normal car calipers with a handbrake on would work? I believe the mk3 sidetrack used Granada brakes

 

[Justme]

Car hand brakes do not meet the required braking force for trailers.

Car hydraulic brakes do not meet the required braking force when they dont have servo assistance.

So not possible to use in a new build.

As you not a new build but a conversion you wont have to prove any of these things.
But I am sure you want the brakes to work well.

As the Sankeys are plated to 750kg max you could remove all brake components but that would be seen as a major mod & need IVA.

 

[sako243]

Car hydraulic brakes do not meet the required braking force when they dont have servo assistance.

Why?! Can you back that up please?

Servo assistance is there to assist the driver, it acts as a force multiplier so the driver can put less effort in to achieve the same braking effort at the wheel. If you lose the (typically) vacuum then you can still stop with the same force but you have to physically put all that force in at the pedal, you don't get any help from the engine. But fundamentally the hydraulics in the braking system will achieve the same braking effort with or without servo assistance.

It's exactly the same with power assisted steering, it's there to assist you but you can still turn you just have to put in a lot more effort.

Incidentally servo assistance is generally not required with drum brakes because as the brakes are applied the simple geometry of the brake drum means that it locks up on it's own requiring almost no effort to maintain the braking effort. Unlike a disc setup which requires constant force to be input to maintain the braking effort.

Main reason brakes have changed from drums to discs is lower maintenance overhead (do not need adjusting), the "race" factor (i.e. race cars had them because they needed the extra cooling) and therefore race stuff is cool therefore it transitioned across to road cars too.

 

[Tinbasherdan]

Car hand brakes do not meet the required braking force for trailers.

Car hydraulic brakes do not meet the required braking force when they dont have servo assistance.

So not possible to use in a new build.

As you not a new build but a conversion you wont have to prove any of these things.
But I am sure you want the brakes to work well.

As the Sankeys are plated to 750kg max you could remove all brake components but that would be seen as a major mod & need IVA.

To be honest if it actually weighs out at 750 I’ll show my hoop in woolies window. I don’t *need* brakes but if it’s fitted for them why not have them. As I said, there’s a vicious rumour that the calipers on the disk brakes sankeys are Granada- might be wrong but they’re definitely nothing fancy in any case

 

[premmington]

Why?! Can you back that up please?

Servo assistance is there to assist the driver, it acts as a force multiplier so the driver can put less effort in to achieve the same braking effort at the wheel. If you lose the (typically) vacuum then you can still stop with the same force but you have to physically put all that force in at the pedal, you don't get any help from the engine. But fundamentally the hydraulics in the braking system will achieve the same braking effort with or without servo assistance.

It's exactly the same with power assisted steering, it's there to assist you but you can still turn you just have to put in a lot more effort.

Incidentally servo assistance is generally not required with drum brakes because as the brakes are applied the simple geometry of the brake drum means that it locks up on it's own requiring almost no effort to maintain the braking effort. Unlike a disc setup which requires constant force to be input to maintain the braking effort.

Main reason brakes have changed from drums to discs is lower maintenance overhead (do not need adjusting), the "race" factor (i.e. race cars had them because they needed the extra cooling) and therefore race stuff is cool therefore it transitioned across to road cars too.

What a well written answer

 

[James1979]

What a well written answer

This one is better

To be honest if it actually weighs out at 750 I’ll show my hoop in woolies window.

 

[Bornfree]

The problem of using car brakes is no auto reverse. Which means getting out and flipping a catch over to lock the hitch every time. Then forgetting and driving off with no brakes. But braking performance with car drum brakes is as good as a dedicated trailer brake. As @sako243 said drums have the self servo effect.

 

[Tinbasherdan]

The problem of using car brakes is no auto reverse. Which means getting out and flipping a catch over to lock the hitch every time. Then forgetting and driving off with no brakes. But braking performance with car drum brakes is as good as a dedicated trailer brake. As @sako243 said drums have the self servo effect.

Sankey drawbar has a reverse block on it anyways

 

[sako243]

The problem of using car brakes is no auto reverse. Which means getting out and flipping a catch over to lock the hitch every time.

A fair few trailers still have this setup. Neighbours brand new 2021 Ifor has this, except they neglected to fit the catch so I came to their rescue with a piece of steel to shove in the hole instead.

 

[Parm]

I will begin by saying I don’t know much about braked trailers

But my my mate has a braked trailer, so I asked how it works. It’s rod operated brakes (probably the wrong description), but hit the brakes in his pick up and some “engineering happens” to operate the trailer brakes. Surely if the same happened with hydraulic they will be better ?

 

[James1979]

I will begin by saying I don’t know much about braked trailers

But my my mate has a braked trailer, so I asked how it works. It’s rod operated brakes (probably the wrong description), but hit the brakes in his pick up and some “engineering happens” to operate the trailer brakes. Surely if the same happened with hydraulic they will be better ?

Rod operated is a good enough description.

Basic hydraulic actuator systems like brakes, ie one input and a simple pipe to an output or three, is effectively a “flexible rod”. There isn’t a hydraulic circuit as such.

The advantage of hydraulic braking is that you can easily multiply the force so you get out more than you put in. Can be done by changing the bore (think finger over a hosepipe) or mechanical assist, like a servo.

A secondary advantage is the “flexible rod” - you can route it wherever you need, not restricted to straight line actuation like the old back brakes on motorbikes

 

[Moose McAlpine]

It’s rod operated brakes (probably the wrong description), but hit the brakes in his pick up and some “engineering happens” to operate the trailer brakes.

Known as overrun brakes.

Truck slows down, trailer hitch "compresses" which activates a lever connected to the rod, which in turn is connected to balancers and cables, the cable pulls a lever inside the drums, pushing the shoes outwards to contact the drums and do the braking.

There's a lag you feel on overrun brakes when they operate.

 

[premmington]

Rod operated is a good enough description.

Basic hydraulic actuator systems like brakes, ie one input and a simple pipe to an output or three, is effectively a “flexible rod”. There isn’t a hydraulic circuit as such.

The advantage of hydraulic braking is that you can easily multiply the force so you get out more than you put in. Can be done by changing the bore (think finger over a hosepipe) or mechanical assist, like a servo.

A secondary advantage is the “flexible rod” - you can route it wherever you need, not restricted to straight line actuation like the old back brakes on motorbikes

Anything is better than the electric system they use in the USA.


Overun brakes you get a "lag" before braking.

Air brakes are where it at - you can feel the trailer pulling back. (But these are expensive - I did once have them fitted to a three axle tilting car transporter behind an early Disco 2 fitted with a compressor).

 

[James1979]

Anything is better than the electric system they use in the USA.


Overun brakes you get a "lag" before braking.

Air brakes are where it at - you can feel the trailer pulling back. (But these are expensive - I did once have them fitted to a three axle tilting car transporter behind an early Disco 2 fitted with a compressor).

Air brakes are the way! Much better than anything else. The landrovers had a conversion for normal brakes on the truck and an air suzie to the trailer. Not sure how it worked mind.

Those electric ones like you get on the fifth wheel caravans used to be illegal here but I think there’s now a way round it with a mod?

 

[mtt.tr]

Anything is better than the electric system they use in the USA.


Overun brakes you get a "lag" before braking.

Air brakes are where it at - you can feel the trailer pulling back. (But these are expensive - I did once have them fitted to a three axle tilting car transporter behind an early Disco 2 fitted with a compressor).

I was towing a reasonably heavy trailer hard brake was required, brakes locked up in the trailer I was unaware of the poor condition the trailer was in.

I stopped dead brakes required MC hammer

 

[premmington]

Air brakes are the way! Much better than anything else. The landrovers had a conversion for normal brakes on the truck and an air suzie to the trailer. Not sure how it worked mind.

Those electric ones like you get on the fifth wheel caravans used to be illegal here but I think there’s now a way round it with a mod?

American caravans and trailers: brakes and couplings

www.gov.uk

 

[Bobupndown]

Can just imagine how ineffective disc brakes on a seldom used trailer would be, discs rusted to buggery

 

[Tinbasherdan]

Can just imagine how ineffective disc brakes on a seldom used trailer would be, discs rusted to buggery

Don’t seem to be an issue with any of my mates who have disk brakes wide tracks

 

[8ob]

I have got an air over hydraulic set up off a landrover mini artic, that uses an air over hydraulic load compensator attached to the back axle to regulate trailer brake pressure.

 

[premmington]

I have got an air over hydraulic set up off a landrover mini artic, that uses an air over hydraulic load compensator attached to the back axle to regulate trailer brake pressure.

Mini artics - I have a thing about these. "I want one"..