Advice needed re Electric Brakes barely working

Hi all.
My electric brakes on the van were hardly working so I replaced the magnets, no better.
Then I replaced the brake shoes, no better.
Now I have replaced the drums as well and they are still no better.

Any advice please, I am getting desperate as we are supposed to be heading off for SA next Tuesday, if we're lucky.

Many thanks, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: disco driver - Tuesday, Mar 11, 2014 at 19:13

Tuesday, Mar 11, 2014 at 19:13
Seeing that it's no better after all that you have done, my advice is
Take it to a brake specialist and/or a qualified Auto Electrician.

It's a bit difficult trying to diagnose the problem on a forum where no one can see the problem physically and well meaning amateurs are offering advice without much to go on.

Disco.
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 19:30

Tuesday, Mar 11, 2014 at 19:30
Thanks Disco,
I'll take any information I can get from whatever source including your advice.

I'll then sieve through it all and see what fits best.

The autolecky is definitely on the horizon. In fact he advised me to replace the magnets.

Many thanks for your input Disco.

Cheers, Bruce
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Member - Andrew & Jen - Tuesday, Mar 11, 2014 at 19:20

Tuesday, Mar 11, 2014 at 19:20
Hullo Bruce
Have just been through the same circus!
I would suggest you check the earth.
Voltage across pins 3 and 5 when brakes fully applied and engine at fast idle needs to be 11.5v or so.
If lower, check thickness of earth wire (6mm min) and make sure pins in connecting plug have no corrosion. Give them a squirt of CRC
Cheers
Andrew
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 20:01

Tuesday, Mar 11, 2014 at 20:01
Thanks Andrew, that's the kind of info I am looking for.

I am about to rewire the brake circuit and to isolate the Break Safe unit to see if it is at fault. I can't exactly see how but not being conversant with the internal circuit I'll try anything once.

My grand nephew is a mechanic and he worked on a similar problem about 2 weeks ago and they replaced everything including the wiring all to no avail. Then, as a last resort, they replaced the brake drums, Bingo.

Well I have done everything and the wiring is the only thing left.

We'll see how it goes.

Your idea will be first up in the morning.
Many thanks.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: Member - Andrew & Jen - Tuesday, Mar 11, 2014 at 20:10

Tuesday, Mar 11, 2014 at 20:10
Hullo Bruce
Don't forget the earth vehicle wiring as well. That was the problem with one of my vehicles (the one that pulled the van).
On the other vehicle (that pulls the C/T) it was corrosion in the plug socket.
BTW, sometimes instead of bringing the earth wire from the brake magnet right back to the plug, manufactures take the earth to the chassis. This connection can cause a problem with corrosion as well, eg if it is pop riveted.
To check the voltage while coupled, I took the top half of the plug off which gave enough room to get the probes on to 3 and 5
Cheers
Andrew
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 22:00

Tuesday, Mar 11, 2014 at 22:00
Pins 3 and 5 are the first on the agenda in the morning Andrew.
I think you have got me headed in the right direction so we will see what tomorrow brings.
I am well prepared to rewire the brake circuit if I have to but we will try the easy things first as Ross suggested also.

Many thanks, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Michael ( Moss Vale NSW) - Tuesday, Mar 11, 2014 at 19:56

Tuesday, Mar 11, 2014 at 19:56
I had a similar problem, they would work perfectly one trip and almost nothing the next time. As they warmed up they got a little better. It will be either the controller or the earth on the body/chassis! Michael
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 20:15

Tuesday, Mar 11, 2014 at 20:15
Thanks Michael, I have tested the controller on the nephew's van last night and it checked out perfect. So I can scratch that one off the list of possibilities.

An earth problem is looking like the best culprit at the moment.
Thanks for the info, greatly appreciated.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: Michael ( Moss Vale NSW) - Tuesday, Mar 11, 2014 at 21:41

Tuesday, Mar 11, 2014 at 21:41
Bruce, Check the earth in the vehicle plug and test the earth in the trailer plug ! Electric brakes are the only way to go but can be very frustrating sometimes! Michael
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 21:56

Tuesday, Mar 11, 2014 at 21:56
Thanks Michael, that will be the first job in the morning. Tomorrow is electrics day as everything else has been done.

The vehicle plug is fine as I tested it on another van last night and it is working fine, even locked up the brakes on the test van so that more or less isolates it to my van. But I will check the vehicle anyway just in case.

Thanks again, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Ross M - Tuesday, Mar 11, 2014 at 20:04

Tuesday, Mar 11, 2014 at 20:04
It is strange an auto elec said to change the magnets without checking if they were the problem. ie stab in the dark.

Physical observation, should reveal if the mechanicals are in good working order. You seem to have done that.

Since they are electric, the supply to the magnets can be checked with a 50w globe in place of the magnet feed wires and when the manual control is applied, not the brake pedal, the brilliance of the globe should vary from off, to glowing reasonably brightly.

This is done by disconnecting the feeds to the magnets (under the trailer) and substituting the globe for the magnets.

It is a pulsed supply from the controller, But just sitting in the vehicle with engine running and pressing the brake pedal won't apply much brake and therefore not much pulsed supply to the trailer UNLESS deceleration is happening. That is why the manual control is used to for test purposes.

A battery's 12v connected directly to the globe and the neg side to the earth wires of the magnets should run the globe full brightness.

If the return to earth is not perfect there will be a resistance and the supply to the magnets cannot flow to negative/earth and therefore the brakes will be weak if there is a resistance in the negative return line. Also the +ve supply must be correct too.

The trailer plug is a vital part as it transfers the energy from the vehicle and allows it to return to the chassis/neg so that must also be perfect in it's contacts. Pins 5 blue and pin 3 white.

These are the things an auto elec would have to do to check the system.

Possibly, you have a bad earthing/negative connection to the vehicle chassis/body/batt -ve.

Check the simple, easy to do items/things first.
If you don't want to do these things yourself then someone who can do it is required. There are a few electrical concepts to be understood in order to do this work.

Cheers
Ross M
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 20:29

Tuesday, Mar 11, 2014 at 20:29
Thanks for the input Ross.
I am begining to suspect that it is an earth problem so that will be the main point of focus in the morning.

I was merely picking the auto electricians brains the other day.
As he had 2 trailers in the previous week with similar problems and he found both to be the magnets so he just suggested replacing those first.

If I cannot get to the bottom of it I will most definitely be heading his way. But I am sure I can get on top of this with a little advice, such as yours and Andrews.

I have had 40 years of hobby electronics experience so I have a fairly good understanding of the principals. It is just that no matter what I try I am not getting anywhere and so i am probably not thinking clearly. Electrics are all that is left. The brakes are working but barely.

Many thanks, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: pop2jocem - Tuesday, Mar 11, 2014 at 20:48

Tuesday, Mar 11, 2014 at 20:48
Maybe a question to be considered is how effective should a van's electric brakes be.
Some have said that you should be able to lock the wheels on dry bitumen. To me locking wheels in any scenario is not what should happen but how do you quantify "working to their limit"?
The brakes on my van being tandem axle 2500 kg ATM 10" drums with 195x14 tyres will not lock the wheels though they certainly let you know they have applied but??????

Cheers
Pop
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 21:02

Tuesday, Mar 11, 2014 at 21:02
Hi Pop,
Locking the wheels is certainly well within the capabilities of electric brakes, however you adjust the settings to a point just before lockup using a set procedure on the Tekonsha Prodegy and that is where it stays set till the next outing, more or less.

When I apply the brakes on my van 'at the moment' the brakes barely work however they have worked well until sometime towards the end of the last outing.

I hooked up the nephews van last night to test my controller and I had the brakes locking up in no time so I readjusted the controller. This however tells me the problem is not with the car but isolated to the van only.

My van must be very similar to yours as it goes 2.5tonne as well and on 10" brakes.

Thank you for your input Pop.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: pop2jocem - Tuesday, Mar 11, 2014 at 22:41

Tuesday, Mar 11, 2014 at 22:41
Hi Bruce,

Maybe I need to have a look at mine. They will certainly lock the vans brakes on gravel. I took it out not long after I bought it about 6 years ago and applied the manual overide to see if all wheels were getting the message. Tried the same on bitumen and with the boost settings on maximum and while they certainly worked and you could feel them pull the van up there was no way I could get them to lock the wheels.
They have never got any better or worse in all that time. I might have a bit of a looksee at all the wiring.
Fair enough to test at the car but I guess each wheels wiring needs checking as well. Bit hard to know what to expect with all that "pulsing" going on.

Cheers
Pop
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Reply By: Axle - Tuesday, Mar 11, 2014 at 21:14

Tuesday, Mar 11, 2014 at 21:14
G/Day Bruce , There was a long time poster on here that towed a large van half way around Oz with the brakes disconnected!, ..No probs, ...The Tojo will handle it mate....LOL.


Cheers Axle.
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Follow Up By: Member - Bruce C (NSW) - Tuesday, Mar 11, 2014 at 21:41

Tuesday, Mar 11, 2014 at 21:41
Thanks Axle,
I know you're right but the thought of disappearing up someones tailpipe has got me shaking at the knees mate.LOL

Ya can't beat a Tojo mate, can ya. LOL

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: pop2jocem - Tuesday, Mar 11, 2014 at 22:29

Tuesday, Mar 11, 2014 at 22:29
I'm reminded of the story of Adolf the brown nosed reindeer.
He was a second cousin to Rudolf.
Apparently he could run as fast as all the other reindeer, he just couldn't stop as quick (;=))

Cheers
Pop
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Follow Up By: Member - Bruce C (NSW) - Wednesday, Mar 12, 2014 at 07:58

Wednesday, Mar 12, 2014 at 07:58
Good one Pop, Hahahahahaha

There will be no brown nosing for this little black duck....... I hope. LOL

You've put a smile back on my face.

Thanks, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Member - Rosco from way back - Tuesday, Mar 11, 2014 at 22:27

Tuesday, Mar 11, 2014 at 22:27
Maybe a silly question Bruce, but have you checked the brake shoe adjustment?
I realise fitting new shoes may sort this, but it's worth adjusting them up and then backing off a tad. Never know .....

No mention of it in the previous posts so I thought I'd ask.
Has made a difference to me in the past.

Plus ignore the "no brakes post" .. maybe in jest, but quite silly also.
Been there done that and it can get bloody scary if you need the suckers and they're not there.
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Follow Up By: Member - Rosco from way back - Tuesday, Mar 11, 2014 at 22:30

Tuesday, Mar 11, 2014 at 22:30
PS. No offence intended Axle old son.
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Follow Up By: Member - Bruce C (NSW) - Wednesday, Mar 12, 2014 at 08:27

Wednesday, Mar 12, 2014 at 08:27
The levity is quite OK by me Rosco, I need a little cheering up at this juncture.

No offence taken Axle.

Before fitting the new magnets I adjusted the brakes, no better.
After fitting the new magnets I adjusted the original shoes again, no better.

Fitted new shoes and adjusted the brakes, no better.

Spoke to my grand nephew who is an apprentice mechanic and asked if he knew much about electric brakes, he replied that they had a horse float in about 2 weeks ago with the same problem and changed everything including the wiring but not the drums. In desperation they changed the drums and bingo, brakes worked.

The drums were worn that far that the magnet could no longer reach the contact face on the drums adequately so brakes were inefficient.

So that was another avenue for me to follow only in my case no change in outcome.
Brakes adjusted, readjusted and readjusted again at every turn.

I will outline what I have found at the end of all of this one way or the other as there are many out there that will come across this problem at some point and the information will be relevant.

One thing is very clear so far.
If replacing your brake shoes in an electric brake setup it is advisable to change your drums as well as the magnets and drums wear out over time. This was the case in the horse float saga.

My drums were well worn although not to a point where they would not have worked, in my opinion.

Now the main observation here is that if changing shoes and drums,
"buy the lot as a complete kit as it is a lot cheaper than buying individual items. A kit comprises 'Backing plate, full mechanisms, shoes, magnets and drums all fitted together' These can be had for $100 per wheel whereas the way I went it has cost me around $180 per wheel.

In fact I would suggest that, given the wear factor between magnets and drums it should be a full replacement after a certain period of time or use. The heavier the van the more frequent the change over. This has been my observation.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Follow Up By: Shaker - Wednesday, Mar 12, 2014 at 08:39

Wednesday, Mar 12, 2014 at 08:39
I don't understand where your grand nephew is coming from, surely if the shoes were properly adjusted it wouldn't matter about drum wear.
I would like to think that they would have tried adjustment prior to replacing other parts. One thing that nobody seems to do any more, is to take in the drums & get the shoes radius ground to suit.
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Follow Up By: Member - Rosco from way back - Wednesday, Mar 12, 2014 at 08:49

Wednesday, Mar 12, 2014 at 08:49
Yep Shaker

But adjusting the shoes won't address the issue of wear on the face that contacts the magnet.
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Follow Up By: Member - Bruce C (NSW) - Wednesday, Mar 12, 2014 at 09:13

Wednesday, Mar 12, 2014 at 09:13
Shaker,
The magnets are attracted to the vertical inside face of the drum when current is applied. This is why the heads of the studs are recessed on the inside of the drum. That shiny surface is a wear surface also.

When the magnet contacts the drum the rotation of the drum moves the magnet and therefore arm the magnet is mounted on rearwards thus applying pressure to the brake shoes to contact the drums.

This means there are two wear surfaces inside the drum on an electric brake setup.
1 Where the shoe contacts the drum.
2 Where the magnet contacts the drums vertical face.

Over time, due to the contact wear, the drums wear down toward the head of the wheel studs as well as the shoes wearing away the drum where they contact.

After some time and extended use the magnet can no longer make a solid and high friction contact with the vertical face inside the drum because it has virtually come to the end of its travel, therefore cannot reach the drum.

Hence the grand nephews comments.

This is why it is advisable to replace the whole shibang, shoes magnets and drums, when upgrading van brakes rather than any one component.

You will notice on the face of the drums it states a maximum diameter.
This is so that once the drum is beyond that tolerance it must be replaced as brake shoe travel distance becomes too great and brake efficiency drops off.

Cheers, Bruce.

At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Iza B - Wednesday, Mar 12, 2014 at 07:51

Wednesday, Mar 12, 2014 at 07:51
Have you established the car or van as the problem? Tow van with a different vehicle or use a different tug to tow vehicle as a quick and easy elimination exercise.

An amp meter in the brake magnets line will also quickly establish whether an electrical or mechanical problem exists. At full 12 volts, most magnets draw about 3 amps each. If the auto electrician sold you magnets without doing this kind of thing first, I would stay well away from that one.

Iza
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Follow Up By: Member - Bruce C (NSW) - Wednesday, Mar 12, 2014 at 08:37

Wednesday, Mar 12, 2014 at 08:37
Thanks Iza,
Yep, as outlined above I have towed the nephews van, which is around the same weight and size, on Monday evening, and was able to lock up that vans brakes so that indicates the problem is with my van and not the vehicle or controller.

This particular auto electrician is a very good one with a very good reputation reputation. He is the sort of fellow who, if he cannot do the right thing by you he will not do anything. I do not have the same level of respect for the others around town, that is how good this particular auto electrician is.

He did not sell me the magnets nor has he had the van to look at, as yet. That may still happen.

Many thanks for the info Iza.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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Reply By: Ross M - Wednesday, Mar 12, 2014 at 10:29

Wednesday, Mar 12, 2014 at 10:29
One bloke a while ago had problems after doing work on his van.

He eventually found he had wired the magnets in SERIES instead of PARALLEL. That halved the energy to the little maggots and they only just chatted with the drums instead of having a serious talk.
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Reply By: garthyguts - Thursday, Mar 13, 2014 at 11:41

Thursday, Mar 13, 2014 at 11:41
dont adjust them like car brakes, adjust to lock up then back off 10 clicks. they need to move to work
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Reply By: Member - Bruce C (NSW) - Thursday, Mar 13, 2014 at 13:52

Thursday, Mar 13, 2014 at 13:52
Hi everyone,
Firstly I'd like to thank you all for your advice and humorous input. Greatly appreciated.

What I have done to this point is I have renewed the shoes, the drums, magnets and wiring and I still have not specifically found what has caused the problem.

The wiring definitely was a contributor in that it was too small for the job or there were some bad connections. Disconnecting the Break Safe unit made no difference and further tests revealed the problem was aft of the Break Safe connections.

I measured 2.3 amps on the last magnet in the run under full brakes and figured that was low compared to the 3 odd amps someone else quoted me and the voltage was down a little also.
Decided to replace the wiring and had some slight improvement after that.
The wiring is of a much heavier grade now, 600 main run and 4mm branches. I doubt that it was 4mm originally, even on the main run.

I am now busy burning the new shoes in and things are on the improve.

I am told that the new electric brakes need some distance to bed in or settle into their work so I am looking forward to that.

Once again, thanks every one for your input. Most appreciated.

Cheers, Bruce.
At home and at ease on a track that I know not and
restless and lost on a track that I know. HL.

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