Finally got around to removing the rear tires and checking the brake drums and linkages, after removing rear tires , any trick to removing the retaining flat head screws to remove drum? Also brake shoes look good but would like to replace the return springs , are they 4104 bus specific or just truck and bus common parts,Thanks
Hit them withKroil or PBBlaster for a day or so let it sit and then try with a hand held impact. Type you hit with a hammer. Or use a punch to try to turn them. Or a screw driver that fits the groove exactly. Hold it in the groove with one hand and use plires on the shaft with the other. They are tough little devils. :)
Nel the manual shows a pair of (smaller) springs for each shoe but on our bus there is only one BIG spring for each shoe. Sorry if I just complicated matters...
Dave is point on with removing the retaining screws. Once I initially got ours loose I put never seize on the threads & the taper and use a small DeWalt battery impact to install & uninstall which is now a breeze.
The original screws were brass and can usually be worked out with the above methods or careully drilled out, or use a 1/2. Drill bit CENTERED to remove head, so drum can be removed, then work on removing stub. If steel screws, and won't come out, you can drill or burn heads off with a torch ( steel melts at lower temp than cast iron, so pretty easily done if you have experience using a torch. Then, work on removing stubs. The springs look like the green ones in picture, but smaller coils and a specific length. I would get them from Luke. Before you order anything, unhook springs, and chamber rods. Check for excessive camshaft end to end play. Remove snap rings holding slack adjusters on. Remove slacks, and remove camshaft. Clean shaft and bore and. Examine shaft bushing area for excessive wear and slop when inserted back into bore. Those bushings are replaceable. Check shoe movement side to side for slop from wear. Luke should be able to provide any parts you will need.
https://www.meritorpartsxpress.com/webapp/wcs/stores/servlet/ProductDisplay?top_category5=&top_category4=&top_category3=&urlRequestType=Base&productId=1997247&catalogId=10051&top_category2=&categoryId=67503&errorViewName=ProductDisplayErrorView&urlLangId=-1&langId=-1&top_category=63501&parent_category_rn=64136&storeId=10154
After spending 2 days removing those retaining screws a few years ago, I replaced them with steel screws of the same shape but with a hex head. Antiseize, and they come off easy with an Allen key.
JC
Good details Chessie. Never seen the retaining screws in brass, but I see all the brake blocks are fastened with brass. We just got done restoring the S cam shaft bushings & seals. Another item on the back I thought was important to bring up ( have on another board) is caulking & undercoating the rear wheel.wells. We are lucky all our airbeams hold air well but I can see where the lack of maintainance (waterproofing) in rear wells could lead to oxidation & corrosion of the air beams especially in northern chloride conditions. My 2 cents anyway.
Also, the beams can corrode from inside out. Once you get salt in those areas, it is difficult to remove. Boaters use a solution called Salt X. I use it on my vehicles at times. On our 4104, the camshafts themselves had much wear to shafts. Had them welded up and reground to original specs. This was before internet days. Also, all new bushings, seals, lining, bolts, and shims to remove any excess play above book specs. Did it once and done.
The drums on my 4106 and our 4108 were held on with brass. Shop here in Milwaukee had no problem replacing them with same. Could this be a regional thing?
Originally they were brass, unfortunately most replace with steel.
Thanks for the help guys, always appreciated.