Rear drums: Seized adjusting star wheel..can't get drum off wheel

[class87]

From: 54PrairieSchooner  (Original Message)
Sent: 4/24/2005 6:27 PM

I'm having one  of a time with my M300 72 Brave..got the left rear wheels off...went to remove the drum and the manual says to push up on the star wheel with a screwdriver..however, it looks as though the star wheel is frozen and I think I am grinding the teeth off...any ideas on how to remove the drum or at worst case, shatter the star wheel to release the pressure on the drum and then replace the adjuster assembly?

John



From: chip
Sent: 4/24/2005 6:48 PM

i think you should be able to twist the heads of the hold down pins for the brake shoes from behind the backing plate with a pair of vice grips. then almost everything will come off with the drum.



From: denison
Sent: 4/24/2005 7:48 PM

I dont know of a good way to undo that star wheel, except perhaps to burn it in two with an acetylene torch, an extremity I have never had to resort to. You usually don’t get good leverage on a star wheel anyway, even when they arent stuck solid.
What is probably holding the drum is the unworn portion of the drum, next to the brake backing plate. It might also be a wheel cylinder piston that is stuck and not retracting, or if you have the parking brake working on the rear drums, it might be a parking brake cable not releasing fully. You might want to try hammering frontways/backways on the brake drum - with the large axle nuts removed, to allow the drum to move around some. A large lead hammer is best for this. If you hammer from the front and from the back, at the 3 o'clock and 9 o'clock positions, it might drive the shoes in far enough to get the drum off. Of course you dont hammer so hard as to distort/crack the drum.
If need be I suppose you could use an acetylene torch to slice the parking brake cable near to the brake backing plate - or try "pushing" the cable to its release position, while you hammer on the drum. You would want to ensure you can get a replacement parking brake before you cut the one you have.
My basic technique is to pull the drum off by main force; dragging it over the shoes. For the force, I use about 10 or 12 ft of chain big enough for the links or an eyelet or clevis to fit over the studs. One end of the chain is placed over a stud and a nut put on to hold it, the other end of the chain goes on an opposite stud. Now you have a 5 ft loop of chain. With a heavy piece of rail or any heavy chunk of iron, (small anvil, spare truck axle shaft) you swing it away from the wheel into the middle of that chain loop, so as to jerk the slack out of the chain. Same principle as a slide-hammer. You will also need to hammer at the 3 o'clock and 9 o'clock positions on the drum now and again, to help the shoes to straighten, and not be cocked at an angle.
I have had this technique ruin the brake shoes, but I was always able to get the drum off intact, and was always able to get replacement shoes.



From: HeavyHaulTrucker
Sent: 4/25/2005 9:05 AM

If you have the time, spray the star wheel with "PB Blaster" -- a great penetrating oil -- and spray the whole thing, even inside the backing plate where the two stubs go out of the wheel itself.  In fact, coat the whole inside of the assembly -- then let it sit for a few hours.  It should then let go and turn.

John
 


From: 54PrairieSchooner
Sent: 4/25/2005 9:27 AM

Thanks for all of the great advice..I'll pick up some PB blaster and try the "graduated" approach...free the star wheel..if that should not work, then I'll twist off the retaining pins..if that doesn't work, I'll try the brute-force "Denison-Method"

Oddly enough, I was worried that I would have trouble getting the flare nut and wheel cylinder retaining bolts loose...all of those came out with no trouble..the flare nut spun freely on the brake line...thanks to the recommended weekly soak of WD-40 on all the fittings....I actually removed the wheel cyliner retaining bolts just in case the wheel cylinder was stuck and holding the shoes against the drums.

R/John



From: Slantsixness
Sent: 4/25/2005 10:23 AM

John,
I don't think you have a parking brake on the rear axle, do you?
I have the Parking brake on the trans tailshaft.

loosening the brake pad adjusters is pretty simple. the P BLASTER is available at Auto Zone (suprise!... they have something for a Winnie!)
If you don't already have a brake adjuster spoon, buy one. it's a whole lot easier

Tom



From: Slantsixness
Sent: 4/25/2005 10:51 AM

John,
One last thought...

you are taking the rear drums off?

do you have the axle out and the wheel bearings too?

or it won't come off!!

Tom



From: DanD2soon
Sent: 4/25/2005 11:02 AM

GOOD / GREAT question, Tom!



From: Boise_Chief1
Sent: 4/25/2005 11:24 AM

Whooaa there hoss.

Read post 7.  Also the star wheel works on a lever that the adjuster wheel "ratchets" on get behind  the lever and pry it slightly out so the teeth don't touch then you will be able to move the adjusting wheel.  I always do this as I'm not a fan of slow.  Once you can move the wheel while holding the lever you can turn it easily and quicker.   



From: 54PrairieSchooner
Sent: 4/25/2005 1:14 PM

My simple mind is confused...do I have to removed the bolts holding the end-cap on what appears to be the rear axle, slide the axle and wheel bearings in order to remove the drum? In other words, drum doesn't budge without removing the entire axle? 



From: denison
Sent: 4/25/2005 2:13 PM

Yes indeed; the axle shaft has to be unbolted and slid out, (they are nuts on studs, and be careful not to loose the small conical items from each of the axle flange holes - they are needed when the axle goes back on), then the large axle nuts inside the hub have to be undone, (I use a cold chisel applied at an angle, to turn the outer nut) then the drum/hub assembly comes off. The wheel studs hold the drum and hub together, which is fine. That hub/drum assembly weighs close to 50 lbs though.
This is easy to say; doing it is on the verge of being backbreaking, but not rocket science. And its much easier when you go to do it to the other side of the RV. I will send you an email with a description I sent to another guy working on his rear brakes for the first time. I would guess it would a little under an hour to get the first drum/hub assembly off, once you have the wheels off. 30 minutes to do the other side another day, after those wheels are off.



From: 54PrairieSchooner
Sent: 4/25/2005 2:28 PM

Dave, thanks...now its all clear to me...I am so used to working on car rear axles that I assumed that the design on a big truck would be similar..not so.  Assume you don't have to remove the differential cover to remove the axle (no C-clip etc.)? Guess I should reread the manual.  It looks like the drums have NEVER been off the rig. The nuts/studs still have the original paint on them....

Thanks again to all of you..now for the fun part. 



From: Slantsixness
Sent: 4/25/2005 3:03 PM

John,

no c clip, but it'll be a fight with a sledge hammer to release the cone washers! watch that they don't pop out and fly where you can't find them! Maybe I'd put a rag over it to catch them if they do fly.....

Tom



From: 54PrairieSchooner
Sent: 4/25/2005 8:30 PM

The left rear axle is out! Based on the advice given and the procedure Dave Denison e-mailed me, I got it out in and removed the outer wheel bearings in about 15-20 minutes...what looked to be really intimidating was really very simple...the drum still won't come off, but I haven't tried to yank it or put PB Blaster on the star wheel and loosen the shoes..I did remove the wheel cylinder bolts and pushed the cylinder down inside the drum just in case the piston was stuck and holding the shoes..I think the adjuster is now sticking. 



From: cooneytunes
Sent: 4/25/2005 9:00 PM

This is not easy but, After spraying with PB Blaster, if it still will not come.
You have to remove the axel, remove the bearing and the bearing cones spacers etc., Put the rear tire back on tight... ..
You'll have more leverage with the inner tire bolted to the drum.  If it still won't budge....this is the hard part... from behind laying on the ground hit the bottom of the tire with a 12 lb sledge....The  wheel bearing cone or cup may be seized up inside the axel housing, and rust and dirt will hold that sucker tight....The drum should come off after a few good hits....
Timmy



From: brakeparts
Sent: 4/26/2005 11:40 AM

What ever you do, don't damage your parking brake cables, because these are not sold in stores...or by me as well. No source for the rear cables.

Secondly, if this was an earlier M300 or M375, then damaging the star wheel unnecessarily would be catastrophic as these parts are unavailable. On the 13 inch rear drums for the 69-71 M300's do nothing to damage the star wheel assy or the adjuster cable that moves it - these are made of unobtanium! The same is true for the front brakes on the 69-73 M375/400 chassis drum brake.

No one needs that kind of aggravation!

Frankly, and I know this is heresy amongst a group of DIYers, If you do not have the skill set to remove or work something, then find someone who does - don't bull your way through it if that means damaging components and risking your own health in hte process.

I do not have any answers here for removal as I do not work on vehicles, but I should think that the Dodge service manual would have the details and someone here might be able to provide same for you.

Good Luck!

Geoff
Alretta Truck Parts Inc.



From: DanD2soon
Sent: 4/26/2005 12:14 PM

It's not taken as heresy, Geoff. Just a much appreciated CAUTION.

I intend to tackle the brakes on mine soon and it is a 1971 M375 Chassis with drums all around...

Your advice won't stop me from doing it, but will greatly affect my attitude in going about it.

Thanks,
DanD



From: 54PrairieSchooner
Sent: 4/26/2005 1:32 PM

Geoff et al: I intend to be very conservative in removing the drums...mine is a 72..is the star-wheel obsolete? Mine will not turn, but if I'm careful, I can get the drum off etc. 



From: DanD2soon
Sent: 4/26/2005 4:59 PM

John,

According to your member survey, yours is one of the units Geoff was warning about... especially if it has drum front brakes too!

ALMOST ALL Dodge Chassis motorhomes were manufactured in the year AFTER the chassis was built - HENCE my 1972 Explorer is built upon a 1971 M375 Chassis - The same is probably true of your 1972 Brave. Mine is registered as a 1972 Explorer, but the VIN on both the Title & Registration confirms it to be a 1971 Dodge (H30/M375) Chassis - And it has drums front & rear so you can bet I'm gonna treat those brake parts LIKE THEY'RE MADE OF GLASS or how'd Geoff put it... UNOBTANIUM!

Later,
DanD



From: denison
Sent: 4/26/2005 5:09 PM

I have to presume you would be able to find a machinist who could duplicate the starwheel part. The price would be -star-tling.
It would be much cheaper to haunt the junkyards, which is my approach. There is/was an M300 or M350 in the junkyard near Gettysburg, if anyone is interested. I think it is a 71, has 8 bolt hubs. I didnt measure the drum diameter or the shoe widths though. If it is still there in 3 months, I might be harvesting parts. 



From: Liv42dayOK
Sent: 1/21/2006 5:17 PM

From: 54PrairieSchooner
Sent: 4/26/2005 7:58 PM

I was finally able to get the drum off by prying with a round bar btwn the backplate and the drum..I noted that I had ground about 3 teeth of the star wheel off trying to turn it..can I still use it?  The shoes are in good shape..one chip on the edge, but it looks like about 1/8" thick on the linings otherwise..should I just retain them...they don't look like there is any brake fluid on them..only a little PB Blaster at the very bottom which I promptly blew off with brake cleaner...?

R/John



From: OldEdBrady
Sent: 4/26/2005 8:52 PM

Well, while you're harvesting, I STILL need the inside plate for the outer coach door!  It's starting to be a real pain, but I can't afford to buy the entire lockset at this time.
 
   

From: denison
Sent: 4/26/2005 10:58 PM

You could re-use that star wheel (quasi-temporarily) while you are looking for a replacement. When the self-adjuster gets to the damaged teeth it probably wont keep "adjusting". That could be thousands of miles from now, if the motorhome is driven only on long trips. If you keep this rig, you would definitely want to remove that drum in a couple of years to check on progress, and replace the star wheel with the one you had found in the meantime. So dimension that star wheel carefully, and take a close photo with a ruler in the picture! I cant help you with a spare part, because my brakes use a totally different type of dual-self-adjusters.
If I was selling my RV, I would tell the buyer of any "issue" with the brakes or the steering.
I dont know the wear limits for the brake shoes. I presume yours has rivetted linings? If I were going to keep the motorhome myself for a few years, I might put a well worn shoe back in - and inspect it again in 2 or 3 years. If I were going to be selling the rig in the near future, I would probably get the shoes relined - as a selling point.
My M400 has the 14” x 3” rear brakes. I “Think” the linings were originally 5/16th thick = .3125”. When I measured them last fall at 96,000 miles, the rear linings were .277” thick, as near as I could see. That’s about .035” of wear. I don’t know if those linings were original, but they were in it when I bought the RV with 49,000 miles on it. Too bad I didn’t measure them at that time.
More-to-the-point; the rivets were all at least 3/16ths (.1875”) below the lining surface at 96,000. When the linings are worn down enough that any rivet is within 1/10” of the surface, I would get them relined. I expect to have another look in there in 2 or 3 years â€" me and my micrometers.



From: 54PrairieSchooner
Sent: 4/27/2005 6:56 AM

Dave, thanks. Its probably the wrong part, but I did find that NAPA carries (for a Dodge M300 Heavy duty truck) a United self-adjuster assembly...Its $21.49...Geoff probably already knows this is the wrong item

Item#: UBP80585

Price: $ 21.49



From: denison
Sent: 4/27/2005 7:05 AM

I hope you are going to buy one and see if it fits?



From: Slantsixness
Sent: 4/27/2005 8:03 AM

John,
It probably will fit! Take your old one with you and see.
Not all brake parts are not available because they're "obsolete"
I know a place in my town that has brake parts people swear are obsolete and unavailable...

I think Denison knows the place too...

I can't say whether they would have the adjuster though.

Tom 



From: 54PrairieSchooner
Sent: 4/27/2005 8:35 PM

I think my shoes are pretty much OK.brake that is.  The book calls for .258, which and mine are right at about 1/4" (using a ruler which I know is crude) measure from the inside of the shoe to the outside surface.  I will likely replace the brake hardware (it looks OK, nothing damaged as far as I can tell) and install the new wheel cylinder and star wheel IF the NAPA part pans out.

John



From: SeaRaySRV16O
Sent: 5/2/2005 9:21 PM

Recently went through trying to locate self adjuster, spring, cable & expander for my '72 w/14" drum on the left front. People I do not think they are out there. The left drum must now be adjusted manually by the owner periodically. When I dissambled the thing I thought the scraping noise I heard was worn shoes. Not so, it was the sound of the expander, the adjuster plate and the broken lower spring, all rolling around in the bottom of the drum.

It had been pulling to the right when I applied the brakes since I bought it, but I have only put a few miles on it since the purchase. The PO had driven it to Michigan from Colorado, and from the looks of the worn parts it was that way in Colorado before he left. I spent a good hour working that expander with lubricant and pipe wrenches to get the threads to screw in & out. Curiously, the expander was apart in three pieces and badly dinged up in the bottom of the drum when I found it. Took the Winne for a run a few days ago & it worked fine after a few stops where the front brakes grabbed pretty bad.

Only thing I really had to have done was have the front drums turned & find a replacement for that broken lower spring. Friendly brake shop parts man gave me a big box of springs to search thru & when I found one that was real similiar, the price was right(free). Shoes looked to have more than 1/4" surface left. Also cleaned & repacked bearings while drums were off. New shocks on the front too. Rides pretty good for bein 33 years old. Next I plan to check rear brakes & new shocks on the back. Ones that came off the front were 1972 OE with Mopar logo & p/n. I may do a junkyard search for that adjer cable & plate, but when I was a kid I adjusted my '53 Chev. brakes every 2 to 3,000 miles. It's no big deal, IMO. Going to run in new fluid as soon as I finish up the rear brake check.

Regards,

Robert Donley
Jenison, MI



From: 72winniebrave1
Sent: 3/8/2006 9:41 PM

Denison,
Was reading through these posts and found this one that you posted regarding an email that you sent someone who was doing his brakes for the first time...if that email you sent to him is still available and is applicable to my 72 Brave, M300 than I'd certainly appreciate it if you could shoot me a copy of it!  Just this evening I cracked into my rear brakes - fortunately without having to use all of the additional hardware, or tools others have mentioned having to use....I was  interested to find out if in your email to him - if you mentioned what the torque value of the rear axle retaining nut is.
Thanks
Rich



From: denisondc
Sent: 3/9/2006 2:20 PM

When you refer to the rear axle retaining nut, do you mean the large diameter nut of which there are two, separated by a keyed lock-ring?
Ideally the best torque for that nut would be about Zero Foot pounds. Quoting from the Dodge Motor Home Service Manual page 3-31: "While rotating wheel and tire assembly, tighten the adjusting nut until a slight bind is evident. Back off the adjusting nut 1/6th turn so that wheel will rotate freely without excessive end play. Install lock-ring and jam nut. Caution: Take care when drawing up jam nut to avoid affecting bearing adjustment due to forcing adjusting nut forward on threads." I did the above but with only the hub/drum in place. The idea is to have no (or very little) end play, but not to have any constant preloading on the bearing either. The reason to overtighten before loosening it, it is to squash extra grease out from between the bearing surfaces, and if you changed the wheel bearings, to fully seat the bearing outer races.
I assume you packed the bearings with grease during reassembly. An essential step! They eventually get lubed by the differential fluid ONLY after driving on the highway for a while, i.e. far enough to ruin bearings that were not packed in grease as well. The long term lubrication is the differential fluid.
In the photo albums of the CW site, in the album titled -Brakes, Budd M375- you will find a picture of the axle retaining nuts. I think its on the 2nd page of that album. The poster left the picture untitled, but it is 000_0648.JPG Photo 000_640.jpg show the nuts with the hub in place.
The nuts that hold the axle flange onto the hub studs are to be torqued to 40-70 ft-lbs if 7/16-20 and 65-105 ft-lbs if 1/2-20. The M300 and M400 are very similar, just some different nut/bolt sizes, one wheel cylinder on each side of the rear axle, instead of two, and other minor differences. Same principles though.
I will look for the email you refer to.



From: 72winniebrave1
Sent: 3/9/2006 5:06 PM

Thanks for your post, Dension - If I'd have taken my disassembly one step further I would've plainly discovered that the hub inner bearing retaining nut beneath the locking tab washer was only slightly more than finger tight....just as you discribed. 

Thanks also for all the other additional info regarding reinstallation - I'll pay close attention where you noted.

For anyone else tackling their rear drum brakes...I found it very helpful while removing my axles to keep the axle flange nuts partly installed on the hub.  Didn't lose or drop a single cone washer -- and with that assurance I was able to concentrate my efforts on getting the axle off.

I did find inside the right rear drum - that the brake self-adjusting cable had rusted through at the guide...due to lack of lube in the cable guide for such a long time.  Anyway, I kept a spare cable from when I did the fronts and would like to keep it for any emergency....but, I was wondering if anyone has had any success with removing the cable from the ends and recrimping them back onto some adequately sized similiar type cable?  Any thoughts would be appreciated?
Richard 
 


From: brakeparts
Sent: 3/10/2006 11:47 AM

Simple answer -

Are these 12 inch diameter drums?

If so, then those adjuster cables are available brand new for $7 each, or the entire adjuster kit for around $24.

It's on the 69-71 13 inch drum chassis that there is a supply issue, or on the 14 fronts for the M375/400.

Regards,

Geoff
Alretta Truck Parts Inc.



From: 75Travco
Sent: 4/5/2006 8:25 PM

I'm reinstalling the brake drums on my 1973 RM-350, and have a question regarding the locking ring that fits between the two axle nuts.  After tightening the outer nut, should one of the tabs be folded over to retain inner nut?  The old ring had been badly mangled so it wasn't clear what the original installation was.

Tightening the outer nut has a marked effect upon the bearing adjustment.  I found that the inner nut had to be backed off about 1/4 turn from "slightly tight" to end up with the proper adjustment.



From: denisondc
Sent: 4/5/2006 9:37 PM

Hopefully someone with an RM-350 will answer.
Meanwhile, you certainly have to -lock- that inner nut from turning on the threads somehow. On the 1972 M400 rear axle the -keyed- ring that fits between the inner nut and outer nut has a series of holes drilled around its surface, and a -tongue- that fits into the notch which is milled in the threaded part of the axle housing. The inner nut has a raised -nub- the same size as the holes in the keyed ring. That nub fitting into one of the holes of the keyed ring is what keeps the inner nut from turning. The outer nut holds the keyed ring in place and backs-up the inner nut.
If your axle is different, you need to do whatever it takes to lock the inner nut. If your axle requires the intermediate ring to be bent over a flat on the inner nut, I have to believe it is a commonly available replacement item - for the same reason that cotter pins are.



From: 75Travco
Sent: 4/6/2006 8:55 PM

There's a picture of the RM-350 axle on the "1975 Travco" album.  The intermediate ring has a key to prevent the inner nut from turning while tightening the outer nut.  I went ahead and folded over one of the tabs onto a flat on the inner nut.  It was a little difficult to do this as the point of the outer nut aligned with the flat of the inner nut, blocking access to the particular tab that needed to be folded.



From: denisondc
Sent: 4/6/2006 9:20 PM

From your picture I would imagine you got the tab folded down far enough to keep the inner nut from moving though. If you wanted to try, could you loosen the outer nut just a little, to be able to get a better -aim- on folding down another tab