Alko Offroad Brakes

Submitted: Wednesday, Feb 09, 2011 at 20:39
ThreadID: 84240 Views:10506 Replies:12 FollowUps:15
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Does anyone know of a good tutorial for fault finding electrical brakes. I have the P3 Tekonsha and new alko offroad electric brakes which I have just fitted. I have read the alko help info and adjusted the brakes so the wheel will only spin one revolution before it stops. The furtherer brake via the wire length from the controller draws 2.3amps under full brake according to my clamp meter,. My problem is the braking is weak. and can not lock up the wheel in a road test but I cant turn it when stationary on the jack either .I thought the two brakes on the single axel should use 2.5 to 3 amps each but have no idea whether 2.3 amps should work the brake successfully or is this my problem?
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Reply By: Shaker - Wednesday, Feb 09, 2011 at 20:56

Wednesday, Feb 09, 2011 at 20:56
The brake wires should really be equal lengths.

AnswerID: 444820

Reply By: Roughasguts - Wednesday, Feb 09, 2011 at 21:11

Wednesday, Feb 09, 2011 at 21:11
Dont' think you really need the brakes to actually lock up do you?

Mine sure as hell don't! but they do pull the van and car up fairly well by just using the thumb slide on the controller.

RememberThey are an inertia brake controller and operate on a pendulum so the quicker you jump on the brake to slow down the better the electric brakes will work (gets more volts). But in a steady braking situation the volts to the brakes are quite minimal say 4-6 volts.

Also these trailer brakes need to get warm to operate more effectively, there not much chop when cold.

Cheers
AnswerID: 444825

Follow Up By: kwk56pt - Wednesday, Feb 09, 2011 at 21:59

Wednesday, Feb 09, 2011 at 21:59
I must admitt I only have tried the brakes when they are cold. I have 5 amps leaving the controller and 5 arriving at the trailer plug and 2.3 to the wheel. I had wired them to one wheel and a tee along the axel to the other. I see not being able to lock them up as confirmation that they are not working as they should.When I apply the manual control no vehicle brake and hence max voltage the braking is weak. How long do they take to warm up as a guide.
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FollowupID: 716973

Follow Up By: Michael ( Moss Vale NSW) - Wednesday, Feb 09, 2011 at 22:12

Wednesday, Feb 09, 2011 at 22:12
Clean the trailer plug and socket and put a thin knife blade through the centre of the split brass pin connector in the plug to get a better electrical connection.
Michael
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Follow Up By: Roughasguts - Wednesday, Feb 09, 2011 at 22:37

Wednesday, Feb 09, 2011 at 22:37
First up you need to run your brake wire to the middle of your axle! then conect each wheel brake wire to the wire in the middle of the axle.
This way there even lengh and will get the same voltage.

Try making a jumper wire for your Earth! that is a wire from your trailer chasis straight to a clean metal Earth on your vehicle.

If this improves the brake performance then theres the problem a shonky earth that can't carry the Amps.

Cheers
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FollowupID: 716996

Reply By: Member - Nick (TAS) - Wednesday, Feb 09, 2011 at 21:13

Wednesday, Feb 09, 2011 at 21:13
Are you trying to lock them up cold or hot.Ours are much the same until the brakes get hot, then once up to temp., they lock up fine.Mind you, the idea is not to lock up.
AnswerID: 444826

Reply By: Michael ( Moss Vale NSW) - Wednesday, Feb 09, 2011 at 21:46

Wednesday, Feb 09, 2011 at 21:46
When my trailer was new and for the first 5 years, you could manually lock the brakes with the thumb slide on the controller, hot or cold, fully laden. The next time i took the trailer out , hardly any brakes and got slightly better when warmed up by holding the thumb slide for a few seconds at a time. I adjusted the shoes to just touching the drums but still no better. I have put up with this situation for the last 4 years with only mild braking with the setting on the controller on full braking. Last year i had a mishap with my trailer axle and damaged the axle so i decided to buy a complete 50 mm sq axle with parallel bearings, Alko off road electric brakes, the ants pants in axles and just got around to fitting it all up a few weeks ago. To my surprise, it behaves exactly the same as the old brakes.
This got me thinking about the source of the voltage, the positive and neg wires are bolted to the battery but the earth was trapped between a few other negative wire loop type connectors and had been sprayed with some gooey yellow anti corrosion spray on goop!! I have since cleaned the terminals and this weekend i hope i have solved the problem when i test again. Although mentioned in this post, its hard to believe you need to warm up the brake linings and drums to get them to lock up. I didn't check the current draw but at the connections to the brake magnet, i got a 9.2v reading. The voltage should drop but i wouldn't think it would to that low if all the connections are good. This was before i cleaned all the battery terminals and connected wires..
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AnswerID: 444841

Follow Up By: kwk56pt - Wednesday, Feb 09, 2011 at 22:14

Wednesday, Feb 09, 2011 at 22:14
Thanks I will check my earth as I wired it to a earth post as there was just to many in total with other accessories to have them all go to the battery teminal. I have a multimeter maybe I could work out how to test the earth.. A good tutorial would be great to provide a framework and parameters to go about a organised trouble shoot. I am told the brake adjustment is important. I have adjusted them as per the instructions on the alko site. Without the controller attached the drums become hot so I have to back these off quite a bit to get the drums to run cool. I then try again with the controller attached and the braking remains weak. I have checked that the left and right drums are fitted correctly and that the backing plate is square to the axel. I have adjusted the brakes up tight to centralise them and then back them off. Its almost as frustrating as brcomming a winner in a nightclub.
I think I need a professional to confirm 5 amps should be doing the job and someone to confirm the brakes are in spec. I found the leading shoe moves but assume the trailing shoe does not move until the lead shoe pushes on the brake drum
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FollowupID: 716981

Follow Up By: Michael ( Moss Vale NSW) - Wednesday, Feb 09, 2011 at 22:19

Wednesday, Feb 09, 2011 at 22:19
I had my new axle built and assenbled by Alko, Melbourne. I thought it would work first go, i will try to adjust the brakes, i ran out of time when i fitted the axle. I will check the Alko site for instructions for adjusting.. thanks Michael
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Reply By: Michael ( Moss Vale NSW) - Wednesday, Feb 09, 2011 at 22:09

Wednesday, Feb 09, 2011 at 22:09
Check the earth and also the positive connection of the controller for good connection.. MIchael
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AnswerID: 444846

Follow Up By: kwk56pt - Wednesday, Feb 09, 2011 at 22:17

Wednesday, Feb 09, 2011 at 22:17
I know I have 5 amps leaving the controller under max brake but should it be 6 for a single axel and is 1 amp the issue
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FollowupID: 716984

Follow Up By: Michael ( Moss Vale NSW) - Wednesday, Feb 09, 2011 at 22:27

Wednesday, Feb 09, 2011 at 22:27
Its hard to believe that 1 amp less would still give you almost no braking!! Im in the same boat as you exactly!! Michael
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Reply By: Member - Graham H (QLD) - Wednesday, Feb 09, 2011 at 22:33

Wednesday, Feb 09, 2011 at 22:33
The correct way to wire them is to have two equal length wires from the A frame or T them in the centre of the axle.

With the P3 you can add boost to bring them on a bit harder as boost 1 starts them at +13%
Gives a bit more oomph

mine will pull me up on the manual slide no trouble
AnswerID: 444855

Reply By: Bob - Wednesday, Feb 09, 2011 at 22:59

Wednesday, Feb 09, 2011 at 22:59
Just replaced backing plate and shoes, drums have also been machined .

Very little braking happening until I went for a run to bed them in . Heat build up could also been a benefit. Will know more tomorrow when they are cold. (Going for rego slip).

Old shoes were badly grooved due to stone damage and wear was uneven possibly due to the brake shoe material having to conform to the shape of the drum ie maximum friction = maximum braking ability. Usually try and adjust for positive braking as felt from drivers seat without lockup but if too aggressive different road surfaces will also cause wheels to lock up.

A few observations.
1. Excessive dust between magnet and drum will reduce effectiveness.
2. Badly worn or unbedded brake shoes will also reduce effectiveness.
3. A stationary wheel is a lot easier to lock up than a rolling vehicle weighing over a tonne or maybe 3 if your using the actuator.
4. If you can feel a positive effect and you know the wiring is in good condition I wouldn't worry too much about current draw.
5 Locking trailer brakes have ruined a pair of BFG tyres (possibly tyre pressures off-road too?)

Sorry for rambling on
Bob
AnswerID: 444862

Reply By: MattR - Wednesday, Feb 09, 2011 at 23:00

Wednesday, Feb 09, 2011 at 23:00
Alko's service manual (page 26) says "about 3 amps" for each brake magnet; I don't know how much leeway the "about" gives you but 2.3 amps seems a little low to me.

If you want, you can test the voltage drop in either the earth or the positive wire with your multimeter, a spare piece of insulated wire, and maybe some help to operate the brake controller and hold wires while you read the meter.

The spare piece of wire doesn't have to be thick at all - 0.5 mm is plenty - you can use old speaker wire or telephone wire or whatever you have lying around. (Thick wire also works; if you have a long pair of jumper / booster cables they will work fine.) It needs to be long enough to get from the battery in the car back to the trailer axle. You are going to use this wire as an extension to one of your multimeter leads; it will be carrying almost zero current.

The earth wire is a little easier to test so try it first. Set your multimeter on the low DC voltage range (1 or 2 or 4 volts, whatever it has) or let the auto-range do what it does. Put the negative / black probe on (important!) **the negative terminal post of the battery in the car**. Don't put it to the car body or frame or anywhere else - go right straight to the negative terminal post of the battery. Put the positive / red probe on one end of the spare wire, and put the other end of the spare wire to a bare piece of metal on the trailer as close to the trailer brake magnets as possible - like on the mounting bolts on the inboard side of the trailer wheel hub. Operate the brake controller in the car and look at the meter.

In a perfect world the meter would read 0.00 volts. In the real world it will read some voltage. 0.1 or 0.2 volts is probably OK but 0.5 volts is marginal and 1.0 volt is definitely a problem. Higher voltages indicate a high resistance somewhere in the earth path from the trailer brake magnets back to the battery in the car. A common culprit here is the multi-pin connector where the trailer plugs into the car - especially the earth wire from the trailer half of the connector to the trailer frame. This wire is often a) too small or b) beat up. The earth wire from the car half of the connector to either the car frame or the battery can also be a problem.

The positive connection is a little harder to test, as you need to access both the output from the Tekonsha brake controller, and the positive wire at or near the brake magnet, while those connections are still connected. Sometimes you can (carefully) poke into the back of a connector with the meter probe while the connector is still plugged in. You will have to use your own creativity to make the connections, but the setup is similar: positive meter probe to output of brake controller at the brake controller, negative meter probe to spare wire, other end of spare wire to brake magnet wire as close to the brake magnet as you can manage. Operate the brake controller and look at the meter.

0.00 volts is perfect; 0.1 or 0.2 volts is probably OK; 0.5 volts is probably bad; 1.0 volts is definitely bad. If you have a high reading, again, check the multi-pin connector where the trailer plugs in, and also the splices at the Tekonsha controller and under the trailer.

I hope this helps!

Matt R.
AnswerID: 444863

Follow Up By: Lex M (Brisbane) - Thursday, Feb 10, 2011 at 00:23

Thursday, Feb 10, 2011 at 00:23
"put the other end of the spare wire to a bare piece of metal on the trailer as close to the trailer brake magnets as possible - like on the mounting bolts on the inboard side of the trailer wheel hub. Operate the brake controller in the car and look at the meter. "


Dangerous assumption. because:-
1. The trailer brake circuit may not connect to the trailer frame near the brakes.
2. The trailer brakes may not connect to the trailer frame at all. Mine don't.
The brake return circuit goes straight to the earth in the trailer plug with no chassis connection on the trailer.













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FollowupID: 717019

Follow Up By: kwk56pt - Thursday, Feb 10, 2011 at 00:42

Thursday, Feb 10, 2011 at 00:42
Hi Matt, thanks for your advice. I did not realise the wires from the T should be the same size As my controller appears to only be sending 5 amps I was wondering what drives this, are the magnets drawing 5 amps or is there a reason this is all they can get. I havent tested the other wheel but assuming the other is using .23 amps also then this 4.6 in total or even if the other wheel is getting 2.5amps then we have 4.8 in total. Does the controller just send what the magnets are drawing, I mean it does not know whether there are 2 or 4 magnets oir if the magnets need 6 amps to work properly I assume it could be trying to get 6 amps but only 5 is available. A clamp metre on the tekonsha side of my join should should tell me what the Tekonsha is sending in the way of amps ? If its sending 6 amps then a wire problem and if its 5 amps well I dont know other than to use your method of checking for voltage drop.
Its probably best to wire the two lengths from the T the same. I did use 6mm wire from the controller so if this was the main issue you would think you would get different amounts of braking to each wheel.
THe main question is why is only 5 amps leaving the controller if we know about 6 amps should be needed
Thanks for your input Matt..............Peter
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FollowupID: 717021

Reply By: Member - Bucky - Thursday, Feb 10, 2011 at 08:31

Thursday, Feb 10, 2011 at 08:31
kwk56pt

I have the same issues !
Almost adentical.
When you figure it out, please let me know.
It cannot be my Irish herritage,
(although some say it is, hahaha, and Roachie...no comments please )

Funny thing the exact same camper (nothing extra done) taken off the Navara Twin Cab 3.0 TD,. Worked brilliantly with the Voyager.
(too good in fact, so I backed the controller right off )

Put onto the Patrol 4.2 TD with the Prodijy Controller is as "weak as"..
All done within 2 weeks, of selling the Navara.
You go figure ?

I have tried many things, but to nothing works
Have upgraded wires to plug (50 amp multi core)
Have upgraded trailer wires to magnets ( 35 amp multi core )
Even the Alko off road magnets.


I will read the posts, and I have also put up posts about the same problem

Personally I recon it's the controller, as I cannot even use the lock up lever !

Cheers
Bucky

AnswerID: 444892

Follow Up By: kwk56pt - Friday, Feb 11, 2011 at 12:47

Friday, Feb 11, 2011 at 12:47
My problem appears the shoes need to be radiused. Apparently common the drums and shoes are new but not matched, that is the radius of the shoes is slightly different to the drum so the shoes need machining to match the drum. Presently I have only some contact withe the shoes to the drum.
I went to the join at the wheel for the magnets. Here I could measure volts and amps with a multimeter. I had 11 vollts and the two magnets were taking 6.5 amps. Apparently 6volts should get decent braking, 11 should lock the wheel up no worries and there ideally should be 12 volts.
So I will get the shoes machined to match the radius of the drums exaxctly and see how that goes. Apparently Alko brakes are made in China
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FollowupID: 717262

Reply By: geocacher (djcache) - Thursday, Feb 10, 2011 at 09:24

Thursday, Feb 10, 2011 at 09:24
Also if it's on an off road trailer you need to make sure you are using off road magnets.

They are different to the ambidextrous on road magnets (cross slot in middle) and have a left & right magnet with a centre core designed not to flog out on corrugations.

Unbenknown to me our trailer had on road magnets in it and after a few thousand km on several trips in recent years we hit the cattle grid just north of Lake Hart this year on the highway & the magnet spun on it's flogged out centre just enough to grab the drum & lock the drivers side wheel instantly.

Cost me a Cooper ST.

Had to completely strip out the inside of the brake mechanism on the side of the highway, after much work to get the brakes to release & turn it back into a free wheeling hub.

Also, a clamp meter is a lousy way of measuring such low current on small wire. Your margin for error is huge.

Are you measuring a single strand at both points that you are measuring? or are you placing it around several wires at once at some point.

If the latter at the back of the vehicle make sure you aren't getting tail light current also.

Current around a circuit should be constant, unless you have a leak to earth or another circuit.

ie. 5 amps into the trailer means 5 amps all the way around, but the voltage at different points will vary according to resistance if measured to earth.

Dave
AnswerID: 444898

Follow Up By: kwk56pt - Thursday, Feb 10, 2011 at 10:36

Thursday, Feb 10, 2011 at 10:36
Yes I used a clamp meter. I put it around one cable to get a reading. I was hoping to find a good tutorial to show me the best way to fault find it. I have a seperate twin 6mm cable going via anderson plugs for the brake. I put the clamp meter around the power cable under the bonnet and at the trailer avdewrson connection and at the brake.I will check the voltage again at the anderson plug, I think it was 12 but I guess it should be the same as at the battery.
Anyone know of a book with a section on how to diagnose trailer brake faults.
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FollowupID: 717060

Follow Up By: geocacher (djcache) - Thursday, Feb 10, 2011 at 16:26

Thursday, Feb 10, 2011 at 16:26
I presume you have the controller mounted in the cab. The voltage at the plug on the trailer between the braking force supply & earth should be what ever the controller is putting out.

Dave
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FollowupID: 717125

Reply By: Shaker - Thursday, Feb 10, 2011 at 09:45

Thursday, Feb 10, 2011 at 09:45
I can't believe that trailer manufacturers are still palming off this archaic braking system.
I have just spent $60,000 on a camper & it has these ridiculously outdated brakes.
Disc brakes were invented over 60 years ago, why are we still accepting ancient technology?
AnswerID: 444906

Follow Up By: kwk56pt - Thursday, Feb 10, 2011 at 10:40

Thursday, Feb 10, 2011 at 10:40
My understanding is electric over hydraulic disc is the best set up. Electric appears to be the most efficient in relation to price at least when they are working.
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FollowupID: 717063

Follow Up By: Shaker - Thursday, Feb 10, 2011 at 12:31

Thursday, Feb 10, 2011 at 12:31
I think you are right, I still have trouble understanding why we persist with drum brakes on trailers, particularly off-road.
If you stop & think about how primitive it is, dragging a magnet across the face of the brake drum.
Imagine if vehicle manufacturers starting fitting drum brakes again!
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FollowupID: 717086

Reply By: Lex M (Brisbane) - Thursday, Feb 10, 2011 at 10:08

Thursday, Feb 10, 2011 at 10:08
I don't understand the problems everyone seems to have with these brakes.

I have a Tvan with 10" Alko brakes on 16" wheels with 205 16 tyres

When cold the brakes will lock the wheels on the first stop. I have to warm them up with gentle manual braking.
On bitumen I set the P3 to 6 volts and on dirt have to reduce it to about 4 volts or lower to stop lockup. I don't use boost, it's unnecessary.

I installed the P3 myself and when I wired it I ran a heavy wire from battery Negative to the ground pin on the trailer plug. Don't forget this wire has to carry the brake light (and tail light) current as well as the brake current when the brakes are activated. I didn't think the original harness was good enough.




AnswerID: 444913

Follow Up By: Roughasguts - Thursday, Feb 10, 2011 at 17:54

Thursday, Feb 10, 2011 at 17:54
I think my van won't lock up cause it's 1.9 tonnes on a single axle.

But if I had the same brakes on my 6x4 box trailer the brakes would lock up no worries.

Cheers.
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FollowupID: 717138

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