Manitou MLT 527 Knott Brakes

[Battler86]

Hi,

I have a Manitou MLT 524 which is giving me a real headache! I removed the Knott slave cylinders on the front axle to check the seal condition and piston bores. I didn't do a full stripdown, just enough to get at the seals..... Popped the circlip out the bottom, removed the spring, knocked out the self-adjuster, and pushed the piston out with an airline. Put back together in reverse order and bolted back down to the axles while resetting the slack adjuster. Bled up a treat.

Problem is, the brakes are binding on after several pedal pushes, and mauling the machine until it won't drive.

I know it's the slack adjusters, which upon releasing the pedal are ramping out as far as they can. As such I've had the slave cylinders off 3 times now, tensioning the slack adjuster spring by a turn, de-tensioning it and removing tension altogether to stop the rotation. The latter of which fixed the issue, but the pedal traveled too far before resistance and the handbrake cable ran out of adjustment before applying the brakes. As such the cylinders are apart once again while I try and figure out how they work.

I can see how they remove slack, but I can't see what limits the travel of the ramp other than at full extension when the pedal releases. The slave cyl bores are tapered where the adjuster sits, which I'm guessing squeezes the floating ribbed clamp around the bottom half of the adjuster shaft and stops it from rotating? Why does this shaft have spiraled grooves machined into it?

So many unknowns and so little information available on them.

Does anyone have experience with these headbangers? Of can anyone explain to me how they actually work and where my problem is stemming from?

Thanks to Acengineering who I've already spoke to by phone. He suggested the adjuster spring wasn't in the correct position. Since then I've tried all positions to no avail.

 

[ACEngineering]

Hi,

I have a Manitou MLT 524 which is giving me a real headache! I removed the Knott slave cylinders on the front axle to check the seal condition and piston bores. I didn't do a full stripdown, just enough to get at the seals..... Popped the circlip out the bottom, removed the spring, knocked out the self-adjuster, and pushed the piston out with an airline. Put back together in reverse order and bolted back down to the axles while resetting the slack adjuster. Bled up a treat.

Problem is, the brakes are binding on after several pedal pushes, and mauling the machine until it won't drive.

I know it's the slack adjusters, which upon releasing the pedal are ramping out as far as they can. As such I've had the slave cylinders off 3 times now, tensioning the slack adjuster spring by a turn, de-tensioning it and removing tension altogether to stop the rotation. The latter of which fixed the issue, but the pedal traveled too far before resistance and the handbrake cable ran out of adjustment before applying the brakes. As such the cylinders are apart once again while I try and figure out how they work.

I can see how they remove slack, but I can't see what limits the travel of the ramp other than at full extension when the pedal releases. The slave cyl bores are tapered where the adjuster sits, which I'm guessing squeezes the floating ribbed clamp around the bottom half of the adjuster shaft and stops it from rotating? Why does this shaft have spiraled grooves machined into it?

So many unknowns and so little information available on them.

Does anyone have experience with these headbangers? Of can anyone explain to me how they actually work and where my problem is stemming from?

Thanks to Acengineering who I've already spoke to by phone. He suggested the adjuster spring wasn't in the correct position. Since then I've tried all positions to no avail.

Still giving you grief! I do hate them Knott cylinders

IMO it sounded like you had it right once! the cylinders and handbrake only have a limited travel so if you had the cylinder right so it wasn't locking on solid then sounds like you have too much wear on the friction discs which the handbrake and pedal cant deal with on one pull/pump of pedal?

how much free play are there on the brake discs between the plates?

The only picture there is of the actuators but completely useless cause it doesn't show how the tangs of that spring are positioned.

From my under standing the spring needs to turn the ramps so it expands and takes out the slack, they are a bugger and I've had your problem before but fortunately for me i dont think i have actually pulled one of them cylinders apart in nearly 10 years and miss them as much as I'd miss a hole in the head

Why did you pull them apart in the first place? what was wrong?

 

[Battler86]

Thanks for the reply Ace, and yep they are still giving me grief.

Got a couple of short vids:

The ones below shows the tangs positioned and the ramps climbing as I think they should. I have not been able stop the brakes locking in this 'mode'.

Next vid shows ramp movement with the spring clicked round so there is no rotational force. To me, this isn't correct, its almost disabling the slack adjusters. But this worked when I built it up. The brakes worked but pedal travel was high and the handbrake was non-existant.

Plenty of life left in the friction discs yet.

Stripped them down as brakes were spongey, turned out to be master cyl which is sorted now.

 

[Battler86]

Solved it.

For anyone else who gets stuck with the same issue....

Rebuild the cylinders, but don't fit the spiral pressure spring or circlip. Put a socket into the vice and sit the slave cylinder on top of it so the pressure slide is sitting on the socket. Get a screwdriver and turn the adjuster anti-clockwise. Then hit hard with a punch through the offset hole. What I didn't realise is that this pushes a bush down over the self-adjuster mechanism. This bush grips the ribbed type friction ring which sits below the lower ramp segment, and stops the assembly from rotating. You'll feel the bush move down until it's a dead blow. Refit spring and circlip and fit slave to axle.

I didn't realise the cylinders needed resetting before fitting to the axle

Thanks for the help Ace, I got there eventually

 

[ACEngineering]

Solved it.

For anyone else who gets stuck with the same issue....

Rebuild the cylinders, but don't fit the spiral pressure spring or circlip. Put a socket into the vice and sit the slave cylinder on top of it so the pressure slide is sitting on the socket. Get a screwdriver and turn the adjuster anti-clockwise. Then hit hard with a punch through the offset hole. What I didn't realise is that this pushes a bush down over the self-adjuster mechanism. This bush grips the ribbed type friction ring which sits below the lower ramp segment, and stops the assembly from rotating. You'll feel the bush move down until it's a dead blow. Refit spring and circlip and fit slave to axle.

I didn't realise the cylinders needed resetting before fitting to the axle

Thanks for the help Ace, I got there eventually

i did tell you they needed resetting on the phone, although you can do that with the spring in place and you only need several a light taps normally.

 

[Battler86]

I was bolting them up partially on the axle then resetting. Only thing I can think of is that while resetting with the pressure springs in the bush was bouncing back, or I wasn't hitting it hard enough.

Either way, they are a nightmare.

 

[Farmer 2 B]

Hello,
just got a 1997 manitou mlt 527 T and the brakes are not working ,pedal stays on the floor , fitted a new master cylinder and tried bleeding but getting no pedal, took slave cylinder of checked it over and all seemed good ,no leaks , so reset it as above post by ACEngineering and Battler 86 described , pumped green fluid from oil can back thought slave cylinder slackened nipple until it half filled the reservoir, bleed system many times while topping up, but still not getting a Hight firm pedal , only near the bottom it gets sort of firm, and does stop the wheels turning by hand. can anyone explain why this is ? also how much space should there be between the brake discs ?
any help would be greatly appreciated thanks.

 

[ACEngineering]

Hello,
just got a 1997 manitou mlt 527 T and the brakes are not working ,pedal stays on the floor , fitted a new master cylinder and tried bleeding but getting no pedal, took slave cylinder of checked it over and all seemed good ,no leaks , so reset it as above post by ACEngineering and Battler 86 described , pumped green fluid from oil can back thought slave cylinder slackened nipple until it half filled the reservoir, bleed system many times while topping up, but still not getting a Hight firm pedal , only near the bottom it gets sort of firm, and does stop the wheels turning by hand. can anyone explain why this is ? also how much space should there be between the brake discs ?
any help would be greatly appreciated thanks.

sounds like the brake discs are worn out, the actuators don't have a great deal of travel on them. With out looking in the book i would guess around 1.5mm free gap on the discs?

 

[Farmer 2 B]

sounds like the brake discs are worn out, the actuators don't have a great deal of travel on them. With out looking in the book i would guess around 1.5mm free gap on the discs?

Thanks for the reply ACE . I have checked the brake discs gap on both sides, the near side gap is about 1 mm and the off side gap is about 4 mm ,how can I be sure the discs are done , as I can se ribbed sides on discs ? can I renew the off side only or do I have to renew both sides ? any idea on discs prices ? Is it a straight forward procedure to replace discs , jack up and prop up , track rods off, axle to chassis bolts off, lower axle, remove dif ring studs, slide out the axle housing with outer hub intact ? what all have I missed out on ? and what next to remove discs ? any specialist tools etc. needed ?
any help would be greatly appreciated.

 

[ACEngineering]

Thanks for the reply ACE . I have checked the brake discs gap on both sides, the near side gap is about 1 mm and the off side gap is about 4 mm ,how can I be sure the discs are done , as I can se ribbed sides on discs ? can I renew the off side only or do I have to renew both sides ? any idea on discs prices ? Is it a straight forward procedure to replace discs , jack up and prop up , track rods off, axle to chassis bolts off, lower axle, remove dif ring studs, slide out the axle housing with outer hub intact ? what all have I missed out on ? and what next to remove discs ? any specialist tools etc. needed ?
any help would be greatly appreciated.

Backlash on discs is 1.3mm to 1.7mm max, so it needs new set of brakes, you will probably find 1 disc on the bad side has completely lost all its lining, not sure why but they do that sometimes. probably find the steel discs have worn grove in the locating pins/dowels too.

No special tools required and baically as you discribed, when you take the trumpet off the discs just pull out off the half shaft.

Let me know if you want a set discs, pins and seals.

 

[Farmer 2 B]

Backlash on discs is 1.3mm to 1.7mm max, so it needs new set of brakes, you will probably find 1 disc on the bad side has completely lost all its lining, not sure why but they do that sometimes. probably find the steel discs have worn grove in the locating pins/dowels too.

No special tools required and baically as you discribed, when you take the trumpet off the discs just pull out off the half shaft.

Let me know if you want a set discs, pins and seals.

 

[Farmer 2 B]

thanks again ace, what is the prices for these parts set discs, pins and seals ?

 

[ACEngineering]

thanks again ace, what is the prices for these parts set discs, pins and seals ?

Private message me your location and contact number, will sort it out over weekend if i get chance or Monday

 

[Farmer 2 B]

Hello, Our 1997 manitou MTL 527 has had the forward / reverse lever bypassed, why would this have been done ? and now operates trough a toggle switch on the dash , I would like to change it back to the original lever, what might this entail ? the fuse board looks to be in reasonable condition, the K2 relay has been removed (Forward gear relay) 2 wires that where going into a multi plug on fuse board are cut and diverted to toggle switch on dash .
small loom with 4 wires all cut of, but 2 have been rejointed and now go to toggle switch on dash, the other 2 wires are just dead ended.
Any help would be greatly appreciated .

 

[Battler86]

Knackered switch? Test the continuity through the switch to make sure it’s functioning. If it is swap the wiring back, but my guess is it’s faulty hence the toggle switch.

As for the other wiring, wouldn’t know without tracing it back or looking at a wiring diagram. If I remember correctly though there’s a limit switch on the brake pedal and handbrake that disables drive, so it’s all interlinked.