| Author |
Message |
david anderson (Davidanderson)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 2:31 pm: | |
Sometimes a little knowledge is dangerous. I read all the archives about brake adjustment, slack adjustment and dove into my manual about slack adjusters. I thought it would be wise to check my brakes. A cursory look showed my driver's bogie way out of adjustment, so I adjusted the worm gear nut on the pawl and screwed it in until it was tight to the drum and backed it out 1/2 turn.
While doing this it really felt loose and I just wasn't comfortable that that there was no lock nut to set the bolt in place. Something just didn't seem right.
The ease of this adjustment led me to believe I had manual slack adjusters. My eagle book showed both. I drove out to a concrete pad at our local airport and figured I would adjust them all this way. I turned the driver's front adjustment bolt until it was tight and uh oh!!, it would not turn back. Crap, I have automatic slack adjusters!!
Now I have my driver's front against the drum and cannot get the proper shoe clearance. I went back to the manual and there is no proceedure to untighten an over adjusted automatic slack adjuster.
What do I do now? I drove the bus home (4 miles) and the drum got about 20 degrees hotter than the other side. It is definitely dragging. The closest bus garage is 40 miles. I'm not sure I can drive it there safely.
Help. Any ideas? How hard is it to remove the pawl assembly. The book shows a retaining ring and a splined shaft. Does it slide off the shaft when the ring is pulled and the clevis unhooked? I may end up creating more problems.
Obviously, I have something wrong with the bogie slack adjuster. It most likely needs to be replaced.
David Anderson
eagle 10 |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 2:58 pm: | |
David,
Jefferson Truck Trailer & Bus Repair
1317 West Reno Avenue, Oklahoma City, OK 73106
(405) 272-0213
Richard |
david anderson (Davidanderson)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 3:49 pm: | |
A little knowledge is dangerous, more knowledge is better. I read the book more thoroughly and loosened the pressure relief nut. Now the bolt can be screwed back. Therefore, I got the driver's front repositioned and the brake chamber stroke to where the book says it should be.
However, I have a real problem on the driver's bogie. The pressure relief nut will not affect the adjustment bolt. The relief spring may be broken inside the pawl. It looks like the beast has to come off for repair or replacement.
The book gives instructions for an overhaul, but a new slack adjuster assembly may be in order here. How much do they cost, and how difficult is it to slide the pawl assembly off the spline?
David Anderson |
T. (Bluegrass)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 5:08 pm: | |
David there is a squir nut on the ajuster that you have to turn with a wrench and then you can turn It, I forget which way that you have to turn It |
T. (Bluegrass)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 5:09 pm: | |
Oh I forgot to tell you that you have to hold It to be able to turn It.
Tony |
Juan Navarro (Jnavarro)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 8:05 pm: | |
My adjusters have a lock sleeve on the bolt. they will only turn when the sleeve is pushed in. I use a box end wrench to do the adjusting, i position the box end over the bolt, push in the sleeve with the wrench and turn. if there is grease and grime buildup, i guess that the sleeve can remain depressed and the bolt can turn either way. I adjust my rears in all the way and back them 1/2 turn, and the front in all the way and back 1/4 turn. I check the adjustment before I leave on a trip and before I head home.
Regards,
Juan Navarro PD4104-148 and PD4107 Buffalo |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 8:22 pm: | |
David--
Glad to hear you got it backed off-- sometimes I have had to remove the slack adjuster itself and reposition it to get back to square one.
New slack adjusters are not that much, call Luke.
--Geoff
'82 RTS AZ |
david anderson (Davidanderson)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 9:04 pm: | |
I think I found the cause of looseness on the driver's bogie slack adjuster worm gear bolt. I pulled the pressure relief nut/pawl spring off. It was a bit deformed. While off, I purged all the old grease out of the slack adjuster. I replaced the pawl nut and spring with the nut from the curbside bogie and it appears to work ok.
Now, on the curbside bogie I had difficulty turning the worm gear bolt in either direction. Upon inspection the darn thing had no grease in it. I had all my brake system worked on a couple of years ago at a bus shop, and it appears this was missed. You don't always get good service even at $65/hour. I'm pissed at myself for not locating both grease fittings on each slack adjuster. I only found one. Now I know better, and it will be done regularly.
I ran out of daylight to finish things up. Tomorrow, I'm going to try to work the curbside bogie worm gear bolt in and out and reinstall the pressure relief nut/pall spring in there and see if it will engage. If not, I'll try a new relief nut/pawl spring. I can't get it locally. I have to go to San Antonio to get it.
I'll update later.
David Anderson |
Tim Jones (Torquester)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 25, 2006 - 10:51 pm: | |
David, I am going to assume that you have Rockwell (Meritor) slack adjusters on your bus. You can verify this by looking at this picture:
http://www.arvinmeritor.com/media/High_Resolution/aftermarket_products/commercial_vehicle_ aftermarket/meritor/CVME008H.jpg
The pawl assembly is the hexagon shaped nut and plunger which is shown in this picture midway between the top and the bottom. If you pull out on the plunger the pawl disengages and the worm adjustment can be backed off. The same effect can be had by unscrewing the hexagon nut and removing the pawl assembly from the slack. It is not necessary to remove the pawl to achieve an adjustment (back off the shoes) , only to pull out the plunger. An inward adjustment of the shoes requires only turning the worm (the pawl will ratchet).
So...to make a brake adjustment turn the worm until it is snug, then pull out the plunger and reverse the direction of rotation on the worm and back off 1/4 turn.
I do this on a daily basis and it is a very simple procedure. I hope that I have explained it so that it can be understood.
Automatic slack adjusters are designed to adjust themselves only when they are getting near the maximum brake stroke for their particular application. In other words ....if maximum brake stroke for your application was 2", the automatic slack might maintain the stroke length at 1-7/8".
Automatic slack adjusters are not supposed to be adjusted manually unless repair work is being performed. They should only be checked to be certain that they are doing their job by monitering brake stroke.
I hope this makes sense, and I hope it will help. Please reply here if you have questions.
Good luck, Tim "Torquester" Jones
'74 Eagle 05, Colorado |
Bryce Gaston (Busted_knuckle)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 26, 2006 - 1:09 am: | |
David, glad you got it working! I see these things neglected all the time! I know its not easy if you don't have good a facility, or or a reliable shop close by but I like to see the whole chassis lubed(& brake adjustment checked at the same time)twice a year even if there are little to no miles put on it. Of course if you drive the wheels off yer coach(which I doubt any of you put as many miles on as a commercial charter coach in a year), it is recommended to do a full service every 8,000 miles and a chassis lube about every 4,000 miles. In a "FULL SERVICE" we change oil,& filters (all), grease EVERYTHING!, check brake adjustments, brake lining thickness, u-joints , rear end, entire drive train, suspension, steering, shocks, tires, wheels, and generaly look over everything on the underside, engine compartment, front access compartments, and just about anything and everything we cans ee and access on the outside of a coach! Now when I say 8,000 we're talking on good ol' two stroke Detroits! On newer units with 60 series Detroits, Cats, & Cummins we do 'em around 15,000 with a chassis lube at 5 & 10. Same with our Big Truck customers! Don't know if any of this helps or not just thiught I share my point of view on preventive maintenance. Busted Knuckle aka; Bryce Gaston |
jimmci9 #2
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 26, 2006 - 6:42 pm: | |
david...... i'll be by tomorrow... ive got a job right out of jourdanton.... you gonna be around???.... |
david anderson (Davidanderson)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 27, 2006 - 8:10 pm: | |
Thanks for showing up Jim. After thorough inspection I found the retainer spring hanging out between the brake shoe and drum on the curbside bogie. So, it turns out I only had a total of 4 brakes on the bus. I pulled the drum off and replaced the springs. Everything else checked out ok. Now all the system is back to book specs.
I feel pretty stupid for not being more astute in thoroughly checking the brake system. It was stopping fine so it was kind of out of mind, so to speak. I'll do it much more often from now on.
David Anderson |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 28, 2006 - 5:25 pm: | |
David,
You're being too hard on yourself. You're not stupid, but you have shown yourself to be astute
Astute: "marked by practical hardheaded knowledge"
You've obviously advanced from ignorance (not a bad thing, in itself) to a state of practical knowledge. What's better, your candidness should help many others avoid the same risk.
Thanks for your responsible diligence respecting this thread. I know there are some that would fail to follow up out of fear of embarassment.
To your credit, Sir!
Onward and Upward |
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