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TR6 MOT Advisories-Brakes


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Can someone please advise the sequence and what to look for/test and inspect  on my TR6 brakes as found on my latest MOT.

On the MOT certificate is states:

  • Oil leak, but not excessive [8.4.1 (a) (i). 
  • Brakes imbalanced, requirements only just met and It would appear that the braking system requires adjustment or repair. Rear (near side reading lower [1.2.1 (b) (i)]
  • Service brake fluctuating, but not excessively - Front [1.2.1 (e)   

On the garage document it states:

  • Minor oil leak . N/S/R brake reading low. Front brake reading fluctuating.

What do we thing it all means, and are they saying that the front brakes are OK?

Thanks and regards, Colin.

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Hi Colin,

 you may well have a leaking brake slave cylinder.

Once the drum is off you will see what is going.

Either renew seals or replace the slave cylinder.

The shoes may be shot but you can put a blow lamp on them to evaporate thew brake fluid off (unless it is DOT5)

New shoes may be a good way to go.

 

Roger

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Ok thanks Roger. So all of these comments in your opinion, are for the rear N/S brake drum only and the other 3 brakes are ok - correct?

If so, I’ll concentrate on this brake only and see what I can find with regard to the leak?

cheers Colin 
 

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The advisory is for brake performance not a leak. A leak of brake hydraulic fluid is either a major or dangerous item as defined under the post 2018 definitions, depending on whether it does or does not affect brake performance in the opinion of the tester. It would be an immediate fail in either case as the tester has no scope to issue an advisory for this.

The oil advisory (8.4.1) will be engine, gearbox or differential with a minor leak which does not meet the criteria for a fail on environmental grounds unless it's bad enough to leave a pool of 75mm diameter within 5 minutes. A brake fluid leak is not covered under 8.4.1 as it's a 100% automatic fail anyway.

It will be a case of cleaning and adjusting the brakes or a seized brake cylinder to replace.

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Hi Colin,

I’m not familiar with UK MOT requirements, but I would start removing both rear drums and brake liners, clean and inspect. Also check the pistons move freely in the rear wheel cylinders. Grease the hand brake cable and make sure both rear cylinders can freely slide in the base plate. Then see if it has improved (5 minute job at MOT station) and do the front side as well if needed.

Cheers,

Waldi

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10 hours ago, FatJon said:

The advisory is for brake performance not a leak. A leak of brake hydraulic fluid is either a major or dangerous item as defined under the post 2018 definitions, depending on whether it does or does not affect brake performance in the opinion of the tester. It would be an immediate fail in either case as the tester has no scope to issue an advisory for this.

The oil advisory (8.4.1) will be engine, gearbox or differential with a minor leak which does not meet the criteria for a fail on environmental grounds unless it's bad enough to leave a pool of 75mm diameter within 5 minutes. A brake fluid leak is not covered under 8.4.1 as it's a 100% automatic fail anyway.

It will be a case of cleaning and adjusting the brakes or a seized brake cylinder to replace.

Ok thanks for that. Yes I have a drip from the timing cover, gearbox and diff, so hopefully the rear cylinder will just need adjusting etc. Thanks for the MOT clarifications Colin 

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Also check for a wear ridge on the backplate preventing any moving parts from sliding freely. It can usually be deal with quite easily with a bit of emery or a light dressing with a hammer. The pic is not a TR but it's a good example of what to look for. To be quite honest I would not go to the trouble of taking the brakes apart without replacing the cylinders if they are of significant age. They're cheap and it's a pain to have to do it again later and inevitably you will have to do it later as they have a hard life. A smear of brake grease never goes amiss either. These moving parts run in a hot and dusty environment and need all the help they can get to stay efficient and reliable.

 

wear.jpeg

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9 minutes ago, FatJon said:

Also check for a wear ridge on the backplate preventing any moving parts from sliding freely. It can usually be deal with quite easily with a bit of emery or a light dressing with a hammer. The pic is not a TR but it's a good example of what to look for. To be quite honest I would not go to the trouble of taking the brakes apart without replacing the cylinders if they are of significant age. They're cheap and it's a pain to have to do it again later and inevitably you will have to do it later as they have a hard life. A smear of brake grease never goes amiss either. These moving parts run in a hot and dusty environment and need all the help they can get to stay efficient and reliable.

 

wear.jpeg

Cheers and thanks for the tips.

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  • 2 weeks later...

So, I`ve taken both rear wheel brake drums off and everything looks clean plenty of brake shoe lining left, and no signs whatsoever of any brake fluid leaks. 

When handbrake levers are pushed away from the backplate, brake pistons move out of the cylinders and push forward shoes out at the top and return when released.

Is there any other parts that should move and return and should the whole cylinder assembly move and return when footbrake is depressed? Also what actually movers the rearward shoe rearward?

Cheers and thanks, Colin.  

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Hi Colin,

I've been doing something similar on my TR4.

With the drum fitted when you pull on the HB lever the leading shoe presses on the drum. This gives a reaction that then moves the rear shoe onto the drum.

As you keep pulling both drums press harder and harder.  However this only hapens IF the slaver cylinder is movable.

My NSR was seized solid.  So although it moved against the drum it didn't easily move back again.

 

Roger

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54 minutes ago, RogerH said:

Hi Colin,

I've been doing something similar on my TR4.

With the drum fitted when you pull on the HB lever the leading shoe presses on the drum. This gives a reaction that then moves the rear shoe onto the drum.

As you keep pulling both drums press harder and harder.  However this only hapens IF the slaver cylinder is movable.

My NSR was seized solid.  So although it moved against the drum it didn't easily move back again.

 

Roger

Ok Roger but how can you prove that it moves with both the foot pedal and hand break with the break drum fitted?

Colin 

 

 

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22 minutes ago, RogerH said:

Hi Colin,

if you can move it (even just a fraction) then it will move.

 

Roger

You mean push the cylinder with say a screwdriver from either side and it should  move a little and then return ?

Colin

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10 hours ago, c.hydes said:

You mean push the cylinder with say a screwdriver from either side and it should  move a little and then return ?

Colin

It may take a mighty push but screwdriver should do it..  IT will return when the drum is on.

 

Roger

Edited by RogerH
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10 hours ago, RogerH said:

It may take a mighty push but screwdriver should do it..  IT will return when the drum is on.

 

Roger

Ok Roger thanks, when pushed with a screwdriver the brake cylinder moves left and right probably about 4mm, but doesn`t return. It has to be pushed again in the opposite direction with screwdriver, is this correct? A small amount of oil on the sliding parts helped it free up a little more.

Colin.

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