Hi, I have looked through the archives to see what information is about, on how I can check my ABS brake system. Basically, the tester at my local NCT test centre , in Ireland, has failed my P38 initially on the ABS not working, and then secondly on the handbrake not having sufficient brake force.

So, the image is of the brake test arrangement as used by my local, and only test centre in Dublin [north], which they insist has been updated to be able to test permanent for-wheel drives.

On my last test, a couple of days ago my P38 failed the ABS test until, after 40 minutes of heated discussions, got the tester to drive the vehicle on the road outside, after which he came back, and with very bad grace, accepted that the ABS "seemed" to be working OK. But then, like a Monty Python sketch, he told me that the vehicle still failed the test because the handbrake had insufficient force - "so there" !

I can accept, to some degree, that the handbrake may not be as good as perhaps it could, maybe it needs tightening up at the adjuster screw on the drum, but the brake is able to hold the vehicle, on the second "click" of the brake lever, on a slight hill even when putting light pressure on the throttle to increase the engine revs. The vehicle doesn't move forward, but, again, I accept that this is not a 100% test of the efficiency of the handbrake. I will try to adjust it tighter this weekend.

So my two main questions are firstly, - how can I physically test the ABS system, and how would I know if the ABS pump is not putting as much pressure out as it should ? Is this possible, that the pump pressure is being reduced by age and use, or does the pump either work or not work, thereby needing replacement.

The second question is - what is the best way to test the handbrake, allowing for the fact that I am doing this outside my house and not in a garage ?

Hopefully, the forum may have some updated advice on this issue.

Oierre3.

What year is the P38 ?? If it's the later Wabco-D version ideally they should not use 2-wheel rollers.

For the handbrake, on 2-wheel rollers it needs both to turn in same direction together. Most rollers do one wheel at a time, so they simply spin in opposite directions !!

RAVE says:

WARNING: Vehicles from 99MY are fitted with 4 wheel traction control, which must
be disabled prior to testing on a single axle dynamometer.

Four Wheel Electronic Traction Control (ETC) Disable Procedure

1. Switch on ignition.
2. Press brake pedal 10 times within 5 seconds of switching the ignition on.
3. Check that the traction control light on the instrument panel has stayed on.
4. The message centre will display Traction Failure and give an audible signal.
5. The traction control will be switched on automatically when the vehicle reaches 7 km/h.

Handbrake adjustment needs to be done with a torque wrench. I had to do mine last week to get it through the MOT.
Leave it in park with the handbrake off and tighten the nut to 25 Nm (I tightened it a more that that at first to centralise the shoes, then set it back at 25 Nm). Then slacken the nut off exactly 1.5 turns. Finally adjust the cable. It should bite fully on the 3rd notch. Often it is rusted up underneath, so maybe a new cable.

Thanks for the very useful information, guys.

Something that occurs to me in relation to the system - I checked the operation of the ABS pump this morning, using the following proceedure:
[1] Switch on ignition, but don't start engine:
[2] Press brake pedal - I can hear the ABS pump start up - keep pedal held down - pump stops. Release brake pedal.
[3] Press brake pedal again, immediately - ABS pump starts again - keep pedal held down - pump stops. Release brake pedal.

This happens each time the brake pedal is pressed. The pump runs for a couple of seconds each time, before cutting out. I can hear the brakes on the back of the car coming on and off.

I am thinking that the ABS pump may be on its way out as I have read that the brake pedal should be able to be pressed down 3 or 4 times before the pump starts up. Does this sound correct ?

Pierre3.

Don't you just love stupid testers? I had one tell me that there was no point in testing my car as the ABS light was staying on until his boss told him it will until the car reaches 5mph. Show him the owners handbook that clearly states that it will stay on until the car is moving so it can check the outputs from the wheel speed sensors.

If the pressure was low the pump would run continuously, the brake efficiency would be low and the TC and ABS lights would be permanently on as the pressure switch would never close to switch off the pump and extinguish the lights.

If they insist on using a two wheel roller, the Traction Control must be disabled as per the instruction posted by Pete above.

Assuming they test the parking brake the same as they do here, they will normally do one wheel at a time which will result in no brake force at all displayed as the opposite wheel will be turning in the other direction. Point out that the parking brake operates on the rear propshaft so both wheels need to be turning at the same time.

The only way you can actually test the ABS is by stomping on the brake pedal on a loose or grassy surface.....

Theres some confusion between ABS and the brake booster here...

ABS functions by turning the brakes OFF, when it detects a locked wheel. Certainly in the UK, the only test for the ABS system is that the light correctly illuminates, then goes off. The P38 catches some testers out because the light doesnt go out until you drive the car. I've had one try to fail me before because the light was on, but after explaining they accepted it was working as expected.

The UK MOT test also states that vehicles with permanent 4wd should not be tested on a 2 wheel brake roller.

The UK test manuals are available online, i would suggest you try to find the irish equivalent and see what it says.

The pump you hear running is the hydraulic boost pump for the brake booster. This replaces the vacuum booster found on most cars with a pressurised hydraulic system instead. The pump should not typically run every brake press, maybe only after 2-3 presses. If its running every time, that could suggest the hydraulic accumulator is on its way out. The accumulator holds a quantity of high pressure fluid ready to be used by the braking system when you press the pedal. If the accumulator has failed, it wont hold enough pressure in reserve and thus will need to restart the pump every time you press the pedal.

NCT Manual is here: https://www.rsa.ie/docs/default-source/services/s4.7-nct/nct-manuals/nct-tester-manual-june-2021.pdf?sfvrsn=4cddfe90_5

Excerpt:

Method of Testing

1. If the vehicle is fitted with an Anti-Lock Braking System (ABS), check that the relevant warning lamp is fitted, and follows the correct sequence of operation (manufacturer’s check sequence
   must be verified).
2. Where possible connect OBD scan tool and check for error codes.
3. Visually check wheel speed sensors are not damaged or missing.
4. Check wiring or other components are not damaged or missing.

So much like the UK, the ABS test is simply a test of the correct function of the warning light.

Hi guys, very many thanks to everybody here, I would like to thank individually but that would just be silly 😁 !!

As Richard says - "Don't you just love stupid testers". Indeed we do, particularly as these people can cause our vehicles to be off the road totally unnecessarily. Like the guy here was insistent that the handbrake with reduced efficiency was a "Fail - Dangerous" fault despite the vehicle being automatic, thereby almost making a handbrake redundant. I agree that it has to work, but in this instance a bit of common sense should have been applied because a "Fail - Dangerous" fault means that it is actually an offense to then drive the car home from the test station. To my mind it should have just been a retest fault.

Aragorn, I have read through the NCT directive manual and unfortunately there is no particular guidance on how to deal with permanent four wheel drive vehicles. It does state that if the vehicle can't be tested in the normal way then it has to be tested by using a Tapley meter or similar but, because the vehicle is booked in at an office you can't discuss the test with any of the testers beforehand. So you have to hand in the keys and a bit later the one of many testers comes out and takes the vehicle to the garage. You, the driver, don't get to interact with any testers until they return the vehicle, at which stage they give you the pass or fail certificate.

I have the opportunity to pick up a complete ABS pump for £200, from a low mileage P38, so I might just take a gamble, buy it, and hope that it solves the ABS problem. A guy here in Ireland, who has a very good reputation with P38's [he's English anyway !!!], did suggest that, without looking at the vehicle that the pump could be on its way out.

I think that I might replace my ABS pump before I get too critical of the NCT testers. I would hate to lambast the fellow only to find that the ABS pump actually isn't performing correctly, and then look like a know-it-all knobhead. At least if I have changed the pump and it is performing in a proper manner then I would feel on firmer ground.

Pierre3.

As said, there's nothing wrong with your pump so you'd just be wasting £200. If the pump is running to get the system up to pressure then cutting out, it is fine. It is when it runs constantly and the ABS and TC lights stay on that you have a problem. The pump supplies pressure to the accumulator which is stored and used to operate the brakes. As said, the ABS system releases a brake when it detects a wheel turning slower than the others so isn't using any pressure at all.

I've just read the manual too and you are quite right, it does say on vehicles that can't be tested on the rollers need testing by the alternative method but nowhere can I find what says is suitable or not. On the section on the parking brake, it does specifically mention brakes that operate on the transmission and say that both wheels must be tested at the same time, not individually.

I would totally disagree that a parking brake is redundant on an automatic. If you take the tail housing off the gearbox and look at the thin steel plate with notches in it that a similarly thin piece of steel slots into, you would see that relying on that to hold the car on any sort of incline is asking for trouble. The parking brake is to stop the car rolling down a hill, not the park position in the gearbox.

Hi Richard, thanks for your invaluable comments.

I haven't ordered the ABS pump yet, so I may as well hold off for the time being. Currently, everything connected to the ABS does operate as it should. I have no problem with the "3 Amigos" so I may just take the old motor back for a retest and see what happens then It is just so soul-destroying to have to go through all these arguments to get through the test, every year.

It's interesting to read your comment on the handbrake versus the park position in the gearbox. I am on my eighth automatic vehicle and I very rarely have ever used the handbrake. I use the handbrake occasionally if I am stuck in traffic and not going anywhere, or at traffic lights if they are slow, but apart from that I never use the handbrake, only the park position in the transmission. Generally, on an incline, I would keep my foot on the footbrake but sometimes I might use the handbrake, but I very, very rarely pull up the handbrake when I leave it parked. I have left it in Edinburgh, on one of the roads up to Prince's Street, for a couple of days just left in park. But, having said all that, I take your advice seriously and consider using the handbrake more often.

Pierre3.

I also use the handbrake always, in all my auto's. The pawl in the parking gear is a weak spot, I see it loading unnecessarily using it to hold the vehicle. Plus I terribly dislike the "clunk" it makes when it disengages, when it has binded with the load of the weight of the vehicle on an incline ....

My procedure is: stop the car - foot on the main brake, gear lever on N - foot on the main brake, handbrake on - foot on the brake, release main brakes, put in P, turn off. Sounds cumbersome, but it takes a second ....
Sometimes I even stop it in N and turn it off, then select P.
For some reason, this has become the norm with the Micra, whose g-box tends to "bind" and selects P with quite an effort ...

I miss out a couple of steps. When I'm pulling up to park it is footbrake on, parking brake on, gearbox into P, engine off and get out of the car. There was someone on the other side that was complaining that with his car in P it would still roll. After checking that the gearchange linkage was correctly adjusted he ended up pulling the transfer case and gearbox tail housing off and finding most of the slots on the park plate had been worn away so the pawl against it was doing nothing. I suspect he (or a previous owner) had been putting it into Park while still moving which had destroyed it, but even so, it is only a bit of plain old mild steel after all.

This turned out to be quite an interesting discussion. I do agree with the mention that pulling the gearbox out of "P" when it is on a hill isn't the best sensation, and I think that from now on I will use the handbrake when parking up. I had never actually given any consideration to how the gearbox "P" works so I also haven't given any consideration about how the vehicle was being held. Silly really, but I suppose that it is a habit going back nearly thirty years !!!

Pierre3.

Re handbrake
If you can bear it, remove the handbrake drum to inspect it...oil contamination in there will limit the handbrake power no matter how much you tighten the adjuster.

The handbrake is also kind of emergency brake (if the main brakes fail), which is why the MOT guys don't like when it doesn't work.

th.

I had never actually given any consideration to how the gearbox "P" works so I also haven't given any consideration about how the vehicle was being held. Silly really, but I suppose that it is a habit going back nearly thirty years !!!

No fault - most people if not all would assume the "P" is just another "gear", like in a manual. Well ... is not 😀

I think the only time the handbrake gets used in mine is when it goes for its MOT 🤣 That said, i have used it occasionally when parking on an actual hill, i just dont do that very often.

Interestingly, earlier variants of the NCT manual had examples in those braking sections about what types of vehicles should be tested with a decellerometer, which included vehicles with permanently engaged 4 wheel drive. At some point circa 2015, they adjusted the wording to simply say "cars of a type that can't be tested". No idea why they chose to add that ambiguity.

The first thing to replace, if your going to replace anything, would be the accumulator. The pump itself is clearly working, but given its restarting so frequently the accumulator may be getting tired.

Its always frustrating when testers have a disagreement like this. I had a similar issue with my old Nissan LEAF. It had a foot operated "handbrake", using a pedal in the footwell. Before the test i'd noticed it was a bit loose, so i adjusted up the rear shoes as per the manual and checked it was all working to spec. The manual says something along the lines of that you should apply 50kg of force to the pedal and it should move 6 clicks. I actually went to the effort of putting a bathroom scale in the footwell to get a feel for how much force i should be applying, and got it all set nicely. Brake felt MUCH better than it had been.

Took it in for its test, and he failed it for too much travel. I decided to overtighten the cable to try and get it passed, and he failed it again. Cue an arguement in the parking lot, i showed him that three clicks on the pedal (half nissans spec!) i could floor the accellerator and the car wouldnt move... He got in and shoved the pedal with all his might and managed to make it move about 12 clicks, and was going "see, too much travel"....

I'm like sure, all your doing there is stretching the crap outta the cables. The brakes were on hard after 3 clicks and you've moved it 12...

After some back and forth he eventually agreed and passed it, but unneccesary hassle and stress for something that i know is working.

I also had them fail my A4 for a non-working engine management light... It doesnt have one. For whatever reason Audi didnt fit the light to models between 1996 and 2000. I ended up taking in the wiring diagram for the instrument cluster, which clearly showed the wiring for the light was "for model year 2001>" and they eventually accepted it.

In both UK for MOT & France for CT if you disagree with the opinion of the tester who failed your vehicle it's easy enough to take it for a test at another more friendly place as there are loads of alternative testing stations. In the UK most garages do MOTs & in France the CT stations just do CTs but they are all independent & there are loads to choose from.

I must admit I had a bad habit of first putting the auto gear lever in P, then putting the handbrake on. I have had to unlearn it.
With all Landrover models, with the parking drum on the back of the gearbox, it allows the car to roll back slightly as the slack is taken out of the transmission. It can mean, on an incline, the weight of the car is held by the gearbox. When you come to take it out of P next time you can feel the mechanism under tension. Not good.
I now stop, put the gearbox in N first, then put the handbrake on, take my foot off the footbrake to allow it to roll back, finally into P.
Another bad habit was to put the box in D to stop the car when reversing, instead of using the brakes.

Again, very many thanks to all you guys, for contributing. It is a great learning experience, and I am very appreciative of the wealth of information.

I would have to agree with Aragorn about excessive forces used by testers - when I went out to my vehicle, after the test last week, the handbrake was pulled up to the last when it was parked up. I pull the brake up to the second "click" which holds the vehicle perfectly well, but after the test I had to use both hands to release the handbrake. This is the kind of thing that really jerks me off, being particularly brutal for no good reason but to see if they can break something and then say "There - it failed because such and such broke".

Dave3d - Yes, I know exactly what you mean about trying to release the "Park" brake when it's on a hill. I do my best to remember to put the handbrake on first, in any automatic, before putting the vehicle in "P", simply because of the shock to the gearbox when you pull it out of "P" and you get a loud bang as it releases !!! To be honest, I never pull the gear selector into reverse or drive when going in the opposite direction, to stop the vehicle. I am so concerned about getting "Gearbox problem" on the dashboard that I really do treat it with kid gloves, probably more than necessary but I just think that if I give everything a really, really easy life then it will last longer. That doesn't always bear fruit !

I think that I might replace the brake shoes, as suggested. I have no idea when the brake drum was last opened so, as mentioned, there could easily be oil or grease in there. At least if I replace the shoes then the drum should be as good as it can be. One question I would ask though is, where and how do you tighten the handbrake cable under the handbrake lever ? I have looked about for information but everything seems to be about replacing the brake shoes and not tightening the cable. I am assuming that there is some adjustment under the centre console somewhere ?

Lastly, in reference to Nigels' post about getting tests in the UK and France, the problem in Ireland is that there are a limited number of test centres because it has all been franchised out to a Spanish outfit called Aplus. There are only three centres within 20 miles of where I live in Dublin and they are usually booked up for 3 or 4 months in advance. I once complained to a government transport minister but his dumbass reply was that he was satisfied that there are enough testing stations based on the number of cars in the country. What a load of bo***x when you have to wait 4 months to get a test !! And at €54 and €28 for a retest.

So, thanks for everyone's input, it is all really useful.

Pierre3.