Neat little trick I learned about meritor slacks...

[allan5oh]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

[Uturn2001]

You just have to pay close attention to make sure it does not pop back in on you or you can do some serious damage to your adjusters.

[allan5oh]

Yup, use the right size screwdriver!

[yoopr]

a Flat screw driver or a teeny tiny little crowbar to fit underneath the Button :P

[Porchclimber]

They actually make a little insert for that.
It's shaped like the claw on a claw hammer with a flat lip at the top.
They hand them out to mechanics.
A HD mechanic friend of mine gave me a couple but the screwdriver works just as good.

[Birken Vogt]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

Taking out the pawl was for the early ones, they did not have the lift disc. The disc came out later (not much later because taking out the pawl was a PITA)

Birken

[bob h]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

It is an auto adjusting slack and should not require regular adjustment.

Anybody still have manual slacks?

Has anybody replaced their auto slacks with manuals?

[bob h]

You just have to pay close attention to make sure it does not pop back in on you or you can do some serious damage to your adjusters.

yeah, if you're using an impact wrench ;0)

use an open end wrench... it should not require much force to turn.

[Birken Vogt]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

It is an auto adjusting slack and should not require regular adjustment.

Anybody still have manual slacks?

Has anybody replaced their auto slacks with manuals?

Have not replaced auto slacks with manuals but have replaced a whole bunch of manuals with autos, used Meritor, Haldex and Bendix autos.

I bet a DOT inspector would catch it if you did, all new trucks since some time in the mid 90s have had to have them.

Birken

[special k]

Any thing built arter Oct. of 96 is supposed to have auto's on it. I have a 96 trailer with manual's on it and they've given me a little lip a couple of times at the scale. I've never gotten a ticket though.

[TRKMechanic]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

It is an auto adjusting slack and should not require regular adjustment.

Anybody still have manual slacks?

Has anybody replaced their auto slacks with manuals?

Have not replaced auto slacks with manuals but have replaced a whole bunch of manuals with autos, used Meritor, Haldex and Bendix autos. I bet a DOT inspector would catch it if you did, all new trucks since some time in the mid 90s have had to have them.
Birken

Using an open end wrench is not going to work that well in the real world. You would be much better off with a 5/16" 8 point socket. Also...even on the newer trucks in our fleet that are well maintained will require a brake adjust on 1 to 2 slacks per truck that are automatics. On older trucks with a lot of miles on them usually 4 or 5 will need adjustment, and really should be replaced(especially the haldex...those do not last all that long).

[bob h]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

It is an auto adjusting slack and should not require regular adjustment.

Anybody still have manual slacks?

Has anybody replaced their auto slacks with manuals?

Have not replaced auto slacks with manuals but have replaced a whole bunch of manuals with autos, used Meritor, Haldex and Bendix autos. I bet a DOT inspector would catch it if you did, all new trucks since some time in the mid 90s have had to have them.
Birken

Using an open end wrench is not going to work that well in the real world. You would be much better off with a 5/16" 8 point socket. Also...even on the newer trucks in our fleet that are well maintained will require a brake adjust on 1 to 2 slacks per truck that are automatics. On older trucks with a lot of miles on them usually 4 or 5 will need adjustment, and really should be replaced(especially the haldex...those do not last all that long).

on tractor drive axles, the socket/ratchet assembly often will not fit... the point was the fact that it requires a great deal of torque to damage a meritor slack while trying to adjust the brake.

[Birken Vogt]

Right, it turns easy in the tightening direction but will not turn in the loosening direction unless the pawl is lifted. The trouble is the other slacks (Haldex, Bendix, etc.) have no pawl and simply require brute force to turn backwards so some of the grease monkeys don't know the difference and will break a Meritor slack that way.

Birken

[bob h]

Right, it turns easy in the tightening direction but will not turn in the loosening direction unless the pawl is lifted. The trouble is the other slacks (Haldex, Bendix, etc.) have no pawl and simply require brute force to turn backwards so some of the grease monkeys don't know the difference and will break a Meritor slack that way.

Birken

ahhhh, it's all come clear to me now!

never even thought of the fact that many guys may have only worked with slacks that use one-way clutch mechanisms!

oh, don't forget that backing these slacks off regularly destroys the clutches... one of the selling features of the A-M slacks.

i was weened on the A-M slacks as i worked in a navistar shop, so i just always compared everyone else's slack to theirs... excuse my ignorance.

[Birken Vogt]

[oh, don't forget that backing these slacks off regularly destroys the clutches... one of the selling features of the A-M slacks.

Good information to know.

The selling feature of the other slacks is the fact that they use one way clutches instead of teeth, hence they have infinite adjustments and will adjust a little bit each time rather than waiting until they click over a tooth like a Meritor one. Whether it makes any practical difference is unknown to me....

I tend to prefer the Meritor ones but I have found that in retrofitting strange and ancient trucks for automatics that Haldex has a much, much broader selection for different applications, as does Bendix but not as much....

Birken

[bob h]

[oh, don't forget that backing these slacks off regularly destroys the clutches... one of the selling features of the A-M slacks.

Good information to know.

The selling feature of the other slacks is the fact that they use one way clutches instead of teeth, hence they have infinite adjustments and will adjust a little bit each time rather than waiting until they click over a tooth like a Meritor one. Whether it makes any practical difference is unknown to me....

I tend to prefer the Meritor ones but I have found that in retrofitting strange and ancient trucks for automatics that Haldex has a much, much broader selection for different applications, as does Bendix but not as much....

Birken

as long as the applied stroke remains decent (nowhere near the stroke limit), you're ok. I've always told my customers to occassionally make a hard brake application while idling across a parking lot (force a full chamber stroke to occur); normal brake applications might not be enough to keep them well adjusted.

[bob h]

***when you are requested to adjust the brakes on a vehicle with auto slacks... the intention is to inspect the stroke, and adjust accordingly***

[JoeyB]

This talk about backing them off against the clutch teeth, I always took a bar under there with me and pulled on the slack while I turned the adjustment. Pull turn pull turn pull turn- just that quick you're done and there's no backing off involved. And I got to see what the actual stroke was (sort of, anyway), which you don't see if you're doing the back-off method.

[bob h]

This talk about backing them off against the clutch teeth, I always took a bar under there with me and pulled on the slack while I turned the adjustment. Pull turn pull turn pull turn- just that quick you're done and there's no backing off involved. And I got to see what the actual stroke was (sort of, anyway), which you don't see if you're doing the back-off method.

never ever thought of that before, instead of backing off. you're measuring the stroke travel, and then tightening down the adjustment only until it's right!!!

thanks for that thought!

isn't it funny how that for years we can overlook the obvious because we've already been taught/shown the "proper" method?

thanks joeyb

...... still can't believe I've overlooked something so obvious for all those years ........... ;0)

[RockyMtnProDriver]

Instead of taking out the adjusting pawl, use a flat screwdriver and "pull" on that round disk. This disengages the pawl. Adjust the brake, release the disk, and "wiggle" the 5/16 wrench to ensure the pawl is set properly. Done!

It is an auto adjusting slack and should not require regular adjustment.

Anybody still have manual slacks?

Has anybody replaced their auto slacks with manuals?

I have manual slacks on one of my flat decks. Although is is permissible to swap manuals with auto's, you cannot swap auto's with manuals. If caught, it could very likely lead to an out of service ticket.

If maintained properly I believe Auto's are superior to manuals.

Although everyone should be trained how to adjust and maintain both types.