[Paul]

I thought about a 4 inch grinder with a cut off wheel but after I had given up for the day. I may can get that in there and just grind it off. Was trying to not touch the slack adjuster just because I never have worked with those but I have the adjusting tutorial if I need it.

i’ll also look into a nut splitter. I’m not familiar with those.

Just placed the order for the hoses and I leave on business reevaluate today so I’ll not get back on this job until Friday. I need the rest!

thanks agin for the support

[John]

Joe, if all it takes is adjusting the slack adjuster, go ahead and do it. It is so simple even Tom can adjust them.

Seriously, if you have the adjusters without the automatic feature get a 9/16″ wrench, push in the metal sleeve over the adjuster, turn the adjuster counter clockwise (or clockwise if that gives better clearance) and when the new chamber is in place turn the adjuster back the other way. You need to adjust them periodically anyway so now’s the time.

[JIM]

Will do on the slack adjuster Jon. Although at this point I’m not sure getting the impact on it will break my problem nut free.

I ordered a nut splitter from Amazon today. States it only goes to 3/4 inch and I need 15/16. I’m hoping it will be 3/16 oversized – doubtfull. Could not find any that go 1 inch.

[Larry]

Use a sharp cold chisel on the nut, running the length of the bolt. A couple good blows with a 10# hammer will split the nut.

Be sure and not hit your hand.

JIM

[Archived]

Bus on ramps and stands, laying on a creeper, swinging a 10# hammer upwards with enough force to anything more than raise a blood blister is not likely. But if I can’t use a 4 grinder on this sucker Friday morning I’ll likely try anything.

Thanks for the suggestions.

[Glenn]

The abrasive cut off wheel will surely work but you will probably end up with grind marks (nicks here and there) from poor aim.

You could also try an air hammer (cheap Harbor Freight type) with chisel.

If the only problem is the slak adjuster in the way, now is the time to get familiar with it. Take it off and clean it up, lube it and understand it. If you need a new rubber boot, install one.

Remove the nut and change that chamber. Reinstall the adjuster and adjust it.

JIM

[Archived]

I second what Jim said. Start with a die grinder with a cut off wheel even if it has to be only 2 inch, they spin 22,000 rpm. Once you get a good groove cut in to the nut introduce the air chisel, you will eventually win. The marriage between the stud and nut will be history forever.

[Liam]

Thanks, I’ll win. Called the guy today that cut in my drive to the barn. He has a torch on his truck to service his backhoe and other equipment. It will come off.

I have some surface rust it that area anyway, so a few burn marks or grinder marks will get taken care of when I clean all that up and put some rust killing paint on it.

[Archived]

Thanks to all your suggestions I made reasonable progress yesterday and an hour this morning. I have now completed 4 of the 6 brake chambers. Work and other preplanned activities won’t let me get back to these for at least a couple of weeks. I’m not sure how common these problems are but I thought I would list the difficult items I’ve encountered so far to better prepare others for this job. After all it is only 2 nuts, one clevis pin and 1 hose per brake chamber (except for the drive which has 2 hoses each). Simple right?

Front axle:

• each chamber had the lower nut that could not be lossened with 1/2 inch impact wrench with 135 psi behind it. I used a 4 inch grinder with a cut off disk to remove those
• one of the cotter pins was welded in so tight I sheared off both ends tying to pull it. Had to use a punch to drive it out, I didn’t have a small enough diameter so now I have a new set of roll pin punches.
• one the clevis pin was “welded” to the yoke, used the grinder again to cut off both sides along the slack adjuster arm.

Tag axle

• threads so fouled with grime two of the bolts sheared off trying to use a 1/2 inch impact to lossen
• both clevis pins welded to the yokes, cut both sides with grinder
• the clevis was also welded to slack adjuster arm so tightly I could not drive it out with a punch and hammer, nor could I push it out with a puller puller. I finally drove it out with a punch in an air chisel.

In fact the clevis pin was so tight I don’t see how I have had any braking action on the tag axel. If the air pressure had moved the slack adjuster, the spring would not have released it. And I have been in a Prevost qualified shop the last two summers and requested a brake inspection and received a “every thing looks great”.

At any rate those 4 are history for 10 years, with new chambers, new hoses and new yokes/clevis pins and slack adjusters set. In total (working by myself) I have about 16 hours on removal and 2 on reinstall.

I’ll get back on the drive axle, later.

[Andy]

What Joe is describing is the result of age and corrosion. I don’t know the age of his brake chambers, but I suspect they either might be original or the coach has spent time in recent years in a salty environment such as the coast or in the rust belt.

And he may be right in that the corrosion may have impacted the operation of the brakes.

But based on what he described I can make some additional assumptions. The cans on the bottom of the air bags have substantial corrosion unless they were recently changed. If he has the leans I would not be surprised if the bottom cans had porosity. The Norgren valves and their bolts were badly corroded. Especially since steel bolts holding them in place were in contact with the aluminum valve bodies.

The good news is when his project is done future maintenance is going to go a whole lot easier because he knows the process and because he won’t be fighting corrosion.

[Peter]

As usual Jon your analysis is right on the money. As I understand the history of the coach it started life in Indiana and then moved south to Louisanna and Texas. The previous owner told me he did not change brake chambers or air bags in the 10 years he owned the coach. ( I priced the coach knowing this and tires essentially out of date). I suspect the chambers are original. They were not leaking but I wanted them gone. I did not expect to find the clevis pins locked solid and it will be interesting to see if I have better braking power now that they are “freed up.”

Prior to the norgren change I did have the leans on the right rear. I’ll be interested to see if they are cured. But won’t be surprised if they are not. I previously had the middle air bag on the right rear replaced because it was leaking at the bottom seal. I don’t see any corrosion on the bottom of the support plates. Between the plate and the bag won’t be known until I replace the rest of the bags. Currently planned for early next year.

Yes it will be earier to maintain in the future and I have learned a lot about the coach in the process. I know much better what needs to be routinly inspected from the underside.

I’ll post back with some additional results as I get back to the job.

[Fred]

Last year I did all hoses and brake chambers plus all air bags new and all norgrens new big job but Dave will not have to worry about it for long time , Tom did drive axle air bags just before I bought it from him and two norgrens at bulk head in front of axle, it’s the way to go unless you don’t mind being on side of road!!!!!! Dave’s bus now will hold air for months in all three tanks!!And I replaced all air bags on gen , plus both air bellows for fan at back

[Peter]

Well yesterday I finally finished the brake chambers on the drive axle. Those nuts were stuborn as well but at least they are high up so I could get a 2 ft breaker bar with and additional 2 feet of pipe to break them free. The original bendix chamber (according to the build sheet and bendix cross reference) were 30/30. when I pulled of the existing chambers they were 30/36 so I went back with 30/36. A much bigger spring and retaining screw/nut. So I know these were changed at least once the 20 year coach history.

All new hoses and chambers, Soap tested joints under pressure and no leaks.

Replaced the double check valve (I hate working in the bumper compartment!) and I now pass Jon’s test.

I’m also feeling the Norgren love today. I set the coach at normal ride height yesterday and turned off the ignition switch. The coach is still in the bubble after 24 hours. Both sides of the rear have settled an identical 1 inch and the front has settled 1/2 inch. Not perfect but I’ll take it. Still sitting just to see when it will bottom out but should be at least 4 days. Of course to get those results I have added air to the aux tank twice. I still have some aux leaks which I will attack this winter.

I also found a small leak at the primary pressure sensor in the bumper compartment. I’ll fix it this winter also. I just could not do another game of twister in that compartment. Still dropping about 30 psi overnight on the primary and secondary. More bus fun to come.

[Archived]

All of us that have started checking for air leaks become obsessed. Sounds like good progress Joe.

Because of the system logic on your suspension system as you know you have to maintain auxiliary air pressure, so your task is doubly difficult.

[Richard]

Nice job Joe…