The right method to test a Defender handbrake on MOT

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Stock_90_TD5_SW

Stock_90_TD5_SW

Active Member
Posts
156
Location
Estonia
Dear forum members,

I live in Estonia and drive a 2006 TD5 D90. Every year in april/may I go to a reputable MOT, where they are rather strict with me and I do all the repairs until the car passes with flying colours.

Yet every year I am involved in an argument with them over the testing of the handbrake strength. They put the truck's rear wheels on a rotating mill, accelerate the wheels and then pull the handbrake. It always shows insufficient power. They then usually torture me a little, converse among themselves and come up with a verdict that it is OK without going into much explaining why they didn't know the right approach from the beginning.

This year they decided to fail me on this (+ the main brake problem, which I'm addressing and have already asked for help in another thread on LZ). But this handbrake testing is bugging me. Can You please share Your knowledge on how this test needs to be done properly? Should it be at all tested on a wheel accelerator?

Thank You for thoughts and comments in advance :))
 
In the UK, the test for a transmission parking brake is:

When testing transmission parking brakes, the minimum parking brake efficiency requirement must be calculated before the brake is tested. As soon as the minimum efficiency requirement is reached the brake testing must cease to avoid any possible damage.

Using a roller brake tester
Run the rollers on each axle that has the parking brake fitted and gradually apply the parking brake, keeping any ‘hold-on’ button or trigger disengaged the whole time.
Continue to apply the brake until maximum effort is achieved, or until the wheels lock and slip on the rollers.
Record the reading at which the maximum braking effort is achieved and whether the wheels locked. Stop the rollers if they haven’t stopped automatically.
 
Thanks, guys!!

MyOldLandy, do You think this method is an effective way to test the handbrake on a Defender? I mean, can a one-axle test as described in the MOT manual apply to a Defender? i.e. should Defender's (for example) rear axle hold as strong as a conventional sedan's handbrake?

Gmacz and Mick1986, do Your trucks pass that test? :D Strange question, but my handbrake can't hold back a lifted clutch:D I guess there IS a problem with the handbrake? Although after having failed that MOT, I parked on a hill and the handbrake held its ground well.. So once again, should the handbrake hold back a lifted clutch in first gear?
 
I've seen my Ninety bounce across the MOT station car park during a HB test, I never went back, current tester is great, no rolling road home sense.
 
Stock_90_TD5_SW said:
Thanks, guys!!

MyOldLandy, do You think this method is an effective way to test the handbrake on a Defender? I mean, can a one-axle test as described in the MOT manual apply to a Defender? i.e. should Defender's (for example) rear axle hold as strong as a conventional sedan's handbrake?

Gmacz and Mick1986, do Your trucks pass that test? :D Strange question, but my handbrake can't hold back a lifted clutch:D I guess there IS a problem with the handbrake? Although after having failed that MOT, I parked on a hill and the handbrake held its ground well.. So once again, should the handbrake hold back a lifted clutch in first gear?
Click to expand...
hand brake should stall the car if in gear with normal start off revs ,with hand brake on if you jack rear axle off the ground turning one wheel will cause the other to rotate in opposite direction due to the diff
 
Stock_90_TD5_SW said:
Thanks, guys!!

MyOldLandy, do You think this method is an effective way to test the handbrake on a Defender? I mean, can a one-axle test as described in the MOT manual apply to a Defender? i.e. should Defender's (for example) rear axle hold as strong as a conventional sedan's handbrake?

Gmacz and Mick1986, do Your trucks pass that test? :D Strange question, but my handbrake can't hold back a lifted clutch:D I guess there IS a problem with the handbrake? Although after having failed that MOT, I parked on a hill and the handbrake held its ground well.. So once again, should the handbrake hold back a lifted clutch in first gear?
Click to expand...

Your handbrake is weak but it still shouldn't go on a rolling road, if they don't have the means to test it they shouldn't test it.
 
Stock_90_TD5_SW said:
Thanks, guys!!

MyOldLandy, do You think this method is an effective way to test the handbrake on a Defender? I mean, can a one-axle test as described in the MOT manual apply to a Defender? i.e. should Defender's (for example) rear axle hold as strong as a conventional sedan's handbrake?

Gmacz and Mick1986, do Your trucks pass that test? :D Strange question, but my handbrake can't hold back a lifted clutch:D I guess there IS a problem with the handbrake? Although after having failed that MOT, I parked on a hill and the handbrake held its ground well.. So once again, should the handbrake hold back a lifted clutch in first gear?
Click to expand...
Mine passed using this method. The handbrake is very good on my 90 and as James says, it will stall the engine at normal revs.
The tester should use the prescribed method in the manual if the equipment is available :)
 
My Old Landy said:
My post was taken from the March 2019 MOT manual :)
Click to expand...

I’m struggling with how your test is described as working for a defender. If the rollers are travelling in the same direction, that will lock the rear diff and transfer motion to the front wheels, making the vehicle move forward. If the rollers travel in opposite directions, then the diff “should” allow both wheels to turn and the handbrake is irrelevant. Other than testing using the clutch or a hill, I can’t see a logical way to testa defender/discovery/RR trans brake. Presumably this is why my last 2 MOT guys and @Gmacz use the method described. Am I missing something?

Mine will stall the engine in first, obviously I’m not sat riding the clutch with the throttle nailed to the floor when testing it, but it’s never failed me.
 
mick 1986 said:
I’m struggling with how your test is described as working for a defender. If the rollers are travelling in the same direction, that will lock the rear diff and transfer motion to the front wheels, making the vehicle move forward. If the rollers travel in opposite directions, then the diff “should” allow both wheels to turn and the handbrake is irrelevant. Other than testing using the clutch or a hill, I can’t see a logical way to testa defender/discovery/RR trans brake. Presumably this is why my last 2 MOT guys and @Gmacz use the method described. Am I missing something?

Mine will stall the engine in first, obviously I’m not sat riding the clutch with the throttle nailed to the floor when testing it, but it’s never failed me.
Click to expand...

All I did was state what is in the MOT manual :) I am not a tester but my handbrake works and passed the MOT in February lol
I have to presume they test it to the rules...... They probably just put it in gear and see if it stalls :D:D:D
 
There is no need to apply the handbrake untill it locks the prop , the decelerometer will give the reading long before the wheels/prop lock ..........the clue is in the name , decelerometer, Like most things in life correct use of the equipment will give the results without risk of causing damage
I carry out the handbrake test by applying the handbrake gently while holding the button in , while moving at about 5 mph, it doesn't take much force to register 16%
 
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