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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: sledhead on March 26, 2020, 04:51:08 AM

Title: brake drum hole size
Post by: sledhead on March 26, 2020, 04:51:08 AM
Hi guys

I got a replacement brake drum for the coach and my guy that is installing them noticed that the 10 x bolt holes are bigger then the old webb drums ?
Webb drums have holes about .878 and the replacements are 1.13 .
He call the supplier and after some investigating was told they are the right replacement for the webb 6685 rev b drums

when he put on the drums on there is a good size gap around each bolt and the parts supplier tells him that after the drive wheels are installed and torqued to 500 lbs all will be good . As he works on dump trucks most of the time he thinks this is not right ?
the old drums are from 1999 could it have changed over time ? 

any ideas ?

thanks   dave
Title: Re: brake drum hole size
Post by: luvrbus on March 26, 2020, 05:30:54 AM
If the hub center matches they are ok,stud pilot drum ?
Title: Re: brake drum hole size
Post by: sledhead on March 26, 2020, 11:17:03 AM
sorry it took so long to get back as my puter is out for a upgrade

stud piloted drum

thanks   dave
Title: Re: brake drum hole size
Post by: luvrbus on March 26, 2020, 12:21:34 PM
Quote from: sledhead on March 26, 2020, 11:17:03 AM
sorry it took so long to get back as my puter is out for a upgrade

stud piloted drum

thanks   dave

They do that now on stud pilot drums so 1 drum works on the front or the drive axle
Title: Re: brake drum hole size
Post by: sledhead on March 26, 2020, 12:43:52 PM
looks scary to me but if it is legal and safe + the 500 lbs that hold the wheel's on I hope all is good .

thanks   dave
Title: Re: brake drum hole size
Post by: luvrbus on March 26, 2020, 01:45:11 PM
Quote from: sledhead on March 26, 2020, 12:43:52 PM
looks scary to me but if it is legal and safe + the 500 lbs that hold the wheel's on I hope all is good .

thanks   dave

That drum most likely works for a hub center application too
Title: Re: brake drum hole size
Post by: sledhead on March 26, 2020, 03:58:54 PM
that's what we were thinking to . It would be nice if there were collar spacers that could be put in to make up the space . I looked up on the webb drum site and all the new replacements are minimum 1" holes .so for now the drums are siting on the floor until I can see if there is any other option out there . As we can't leave home anyway with this covid 19 thing. now that the brakes are done and found a inner axle seal was just started to leak has been replaced and a new exhaust system it is time to change out the rear end fluid as I am sure it has been in there for 20 years . But after draining it ,it looks good ? then it is to the transmission and replace the o rings in the lines a the transmission that are leaking a few drops and change the trans. fluid and filters again to finish the change to syn fluid .
After that I think all my up keep will be done

dave     

Title: Re: brake drum hole size
Post by: luvrbus on March 26, 2020, 06:17:37 PM
Look at the space on the studs on the rear axle putting the wheel on
Title: Re: brake drum hole size
Post by: sledhead on March 27, 2020, 04:26:10 AM
It looks like the drum centers good on the wedges that are there but what happens when the brakes are hit hard when some dumb @$# cuts if front of me ? time will tell

thanks  dave 
Title: Re: brake drum hole size
Post by: luvrbus on March 27, 2020, 06:35:55 AM
They won't even shear the bolts holding the drum to hubs all the ones I have seen Webb is not going to sell you drums that would endanger your safety
Title: Re: brake drum hole size
Post by: chessie4905 on March 27, 2020, 07:11:26 AM
If the holes are larger than stud size, picture which way the drums would try to rotate vs the wheels upon a major stopping event. Rotate the drum slightly against that side of the studs. Although I would think that 10 stud/nut clamping force of 450 lb. ft. would not allow the drums to shift.
Title: Re: brake drum hole size
Post by: luvrbus on March 27, 2020, 07:24:36 AM
I am sure he can find old stock if he worries about it but drums have been like that for awhile ,the 1st I saw was on a Prevost and the holding screws were still intact
Title: Re: brake drum hole size
Post by: buswarrior on March 27, 2020, 07:31:30 AM
Here's what these (profanity deleted) ads embedded in the middle of thread showed me just now....

I thought there was some comedy... but its just google... beware, they get much better, the meaning of threads will get skewed...
Title: Re: brake drum hole size
Post by: luvrbus on March 27, 2020, 08:32:02 AM
Meritor has some good reading about brake drums on the internet
Title: Re: brake drum hole size
Post by: brmax on March 27, 2020, 08:54:28 AM
The garbage ads allowed by the site will be its end. Just as many before.
Sad to hear but the dam fact.

Have a good day
Later!
Title: Re: brake drum hole size
Post by: luvrbus on March 27, 2020, 09:14:23 AM
My granddaughter did something I no longer get the ads only the ones at the top now that are paid advertisers   
Title: Re: brake drum hole size
Post by: buswarrior on March 27, 2020, 09:43:43 AM
Quote from: brmax on March 27, 2020, 08:54:28 AM
The garbage ads allowed by the site will be its end. Just as many before.
Sad to hear but the dam fact.

Have a good day
Later!

We are an income stream.
Title: Re: brake drum hole size
Post by: Dave5Cs on March 27, 2020, 10:31:39 AM
LOL Clifford yea Granddaughter! :)
Title: Re: brake drum hole size
Post by: sledhead on March 27, 2020, 03:18:48 PM
all's good when I get to the point of installing the wheels on the drums I will.

after all what is the worst that can happen !

it wouldn't be the first time a set of duels went flying down the highway

8)   dave
Title: Re: brake drum hole size
Post by: uncle ned on March 27, 2020, 04:31:42 PM

On cars and big trucks the hub centered wheels and the lug centered wheels have different size holes and studs.  according to my truck owner friend .

I talked to him about the super singles he ran on his trucks,
He told me the price of the wheels and tires.

I told him I would just buy mine from the midnight supply store.

That is when he told me about the size of the studs on Huggy and hub centered wheels.

uncle ned
Title: Re: brake drum hole size
Post by: sledhead on April 12, 2020, 05:23:02 AM
UPDATE

so all is back together and I went for a drive to see how everything was doing . had some vibration on the passenger side ? not bad but it was not there before the repairs ?
when I installed the wheels back on the coach I tried to keep the drums centered as much as I could but the driver side was close and the passenger side moved by the time I had the wheels torqued ?
after I returned home I removed the passenger wheels and the drum was off center . so after scratching my head I made 8 x 3/4 " nylon hose spacers 4 " long and slid them through the drums with the parking brakes off on 8 of the 10 bolts before I put on the 1st set of wheels removing the spacers 1 at a time as I installed the studs . torqued them down and put on the outside wheel and torqued that as well .
went for another drive and the vibration is gone ?? so now I will redo the drivers side as well and have to carry the spacers with me in the coach just in case they are needed with a flat .

so no they do not work as they should ... just another good enough fix by the parts supplier to not make the drums like they were made back in the day .

but the brakes work better then before and I like the new truck muffler  8)

dave 

   

Title: Re: brake drum hole size
Post by: chessie4905 on April 12, 2020, 09:35:58 AM
That shouldn't effect balance. Wheels were mounted in different indexed position than before? New drums aren't balanced?
Title: Re: brake drum hole size
Post by: richard5933 on April 12, 2020, 01:47:07 PM
Would kind of make sense - if the holes are enlarged in all directions it would be possible for the drum to be slightly off center.

Are you using the screws that hold the drum to the hub?

I'm wondering if those drums are being designed for use with hub piloted wheels. If so, they rely on piloting tabs on the hub to center the brake drum.

If the drums have holes too big for the studs and your hubs are stud centering, then it's touch to get things lined up.

Here's something I found that sounds similar to what you did, but it is more permanent.

https://www.tru-bal.com/brake-drum-spacers

They have a video on their site which shows what can happen if the alignment tabs for the drum wear, which sounds like the problem you're having since you don't have the tabs at all.
Title: Re: brake drum hole size
Post by: chessie4905 on April 12, 2020, 02:13:26 PM
The hub bore is the same for stud piloted and hub piloted . One uses a metric dimension and the other in inches, but do the conversion math. Both are same size.
Title: Re: brake drum hole size
Post by: richard5933 on April 12, 2020, 02:36:18 PM
Quote from: chessie4905 on April 12, 2020, 02:13:26 PM
The hub bore is the same for stud piloted and hub piloted . One uses a metric dimension and the other in inches, but do the conversion math. Both are same size.
But, on a stud piloted hub what would be there to align and center the drum? Doesn't a hub piloted hub have the tabs sticking out to do this?
Title: Re: brake drum hole size
Post by: chessie4905 on April 12, 2020, 04:31:36 PM
Find a GM listing for two different hubs.
Title: Re: brake drum hole size
Post by: sledhead on April 13, 2020, 05:39:27 AM
Richard thanks for the link !
that is the fix I need and will call them to make sure I get the right one's . but for now I redid all the drive wheels and the ride is
smooooooth with out the vibration . I did ask my parts guy back when we got the drums and he did not know of any spacers ? Now I will send him the link

thanks   dave
Title: Re: brake drum hole size
Post by: luvrbus on April 13, 2020, 06:26:29 AM
Quote from: chessie4905 on April 12, 2020, 04:31:36 PM
Find a GM listing for two different hubs.

MCI used the same hub for pilot and hub centering since the 70's,now the new drums are made to fit both,lol I had 2 packs of those spacers that came from a MCI order and never knew what they were for but they were not needed on my MCI
Title: Re: brake drum hole size
Post by: sledhead on April 13, 2020, 12:17:39 PM
The plot thickins
I told my parts guy about the spacers and he told me about bud nuts that he can get that have the washer / spacer built on the nuts / bolts ? so I have not seen them yet but he tells me that they are not that much $$$ so I stuck my neck out and told him to order a set of LH and a set of RH with new nuts as well ? I hope his idea and my idea on not to much money are the same ? I should know more by the end of this week , will let you know

   dave
Title: Re: brake drum hole size
Post by: chessie4905 on April 13, 2020, 12:43:31 PM
Is he talking about these?
https://www.lawsonproducts.com/lawson/Right-Hand-Inner-Cap-Nut-for-Dual-Aluminum-Wheels/62437.lp
Title: Re: brake drum hole size
Post by: richard5933 on April 13, 2020, 02:26:23 PM
How would that help the drum stay centered? I'm assuming that the wheel still fits the drum properly, so how would that lip protrude through to center the drum? Or am I looking at this upside down?
Title: Re: brake drum hole size
Post by: luvrbus on April 13, 2020, 03:28:06 PM
Those nuts are for when you are running Alcoa's on the inside wheel they never touch the drum,you don't use that nut when running steel wheels on the inside lol or you have a loose steel wheel on the inside 
Title: Re: brake drum hole size
Post by: chessie4905 on April 13, 2020, 04:27:53 PM
Thats my thought also. But maybe if you have steel inner wheels and use the inner nut for aluminum wheels, the extra length may keep brake drum centered??? How do you keep drum centered till you install wheel and buts?Don't the new drums have the holes for screws?
Title: Re: brake drum hole size
Post by: chessie4905 on April 14, 2020, 04:23:18 AM
How about giving Luke a call about this. I'm  sure he's  dealt with this issue over the years.
Title: Re: brake drum hole size
Post by: sledhead on April 14, 2020, 04:56:29 AM
no holes for screws in the drums and until I see the bud bolts/ nuts I do not know how they work . I do know that my hose spacer did the job to hold the drums centered so I could get the inner wheel on and get it torqued and then the outer wheel as well . I hope the 500 lbs of torque will hold the drums from moving when the brakes are applied

dave