Axle and brake help
 

Ok here is a head scratcher for me and I'd appreciate any help given, so I've got a 71 GMC K2500 that somewhere along the line a previous owner put a Dana 70 DRW axle under... I've identified it a a Dana 70 from the bottom passenger side gusset on the differential housing. The serial number stamped into the passenger side axle tube (if I remember correctly, I will re-look/ take pictures in the morning) identifies it as an mid 80s (84 I believe) Dodge W350 axle. With all that info I am having a hellacious time finding the rear shoes... They measure out to be 13x2.5, but NONE of the shoes I can find have the correct/ same holes for springs and hardware. I've included (horrible) pictures if they help. The pictures are of the passenger side and the rear shoe seems to have been manually drilled to accommodate the paking/e-brake "pivot arm". I can readjust or redrill new shoes to match if need be but the closest myself and ANY parts store or brake specialist near me has come up with is the Wagner Z320R shoes but the top spring "hole" is in the wrong place. Again any help would be greatly appreciated.
PS the drums only say "BUDD 96125" on them.
I would also like to point out that a few parts seem misplaced in the pictures to me... These are before I took anything apart... AND no the rears have never functioned since I've had the truck. ( I think there is air in the line and the wheel cylinders leak)

Re: Axle and brake help
 

See if any of the 13" here look right:

https://www.rockauto.com/en/catalog/...rake+shoe,1688

Re: Axle and brake help
 

The 2 13" rears I see in there are the same as the Wagner Z320R(s) just different part numbers for different seller. I've also been scouring Rock Auto... Too bad RA doesn't let you look parts up by item name (ie 13x2.5 brake shoes) �� Thank you though��

Re: Axle and brake help
 

...or you could look up shoes by the part number of the drum they go to

Re: Axle and brake help
 

Tried, I personally can't find anything for "BUDD 96125" Brake drums... The internet does not like me or it could just be that I've been at this most of the day and I've gotten increasingly dumber by the hour staring at all the numbers and cross-reference numbers *sighs*

Re: Axle and brake help
 

These guys have several different drums for that Budd number. No shoes listed, but maybe if you call that CS number they can match you up

Re: Axle and brake help
 

By "These guys" do you mean Rock Auto? If so I hadn't even thought to call... *facepalm* I will try that in the morning thank you.

Re: Axle and brake help
 

No, I went too fast and dropped the link:
https://www.durabrake.com/literature/part_list.pdf

This random listing on evilbay might be relevant:
https://www.ebay.com/itm/394051969044

Re: Axle and brake help
 

Re: Axle and brake help
 

Called Durabrake.... The guy essentially laugh at me... In a nice way. The brakes on this thing are completely wrong apparently. It has the wrong spring set and a previous owner apparently just drilled holes in brake shoe to be able to mount them. He can't find a proper picture... But they aren't mounted in a way that he has ever seen. It is missing the adjuster "plate" that keeps it from backing off and the springs are completely wrong, According to him. So... I'm back at square one 😭

Re: Axle and brake help
 

All facts are friendly. At least you know.
Maybe find an old motorhome in the scrapyard on an M300 chassis(there were a lot of them) and rip the guts out of the brakes.
OR scrounge up a GM rearend and never have to deal with a Frankentruck again

Re: Axle and brake help
 

Went to the local yard, found a 74 full float D60 that needs a pinion bearing I can feel/hear it making a grinding... Or I found a 75 Ford F250 full float D60 that with what appears to be a Detroit locker (4.10 gears) BOM says it has 3.73 but metal tag says 4.10 with the Ford locker part number stamped on it also... What do you think?

Re: Axle and brake help
 

Out of my comfort zone to advise you there, tbh, sorry. Gonna be some rust above the "waterline" but maybe in the desert, that's superficial :shrug:

Maybe some grizzled veterans can chime on their experiences

Re: Axle and brake help
 

Thank you for the help so far

Re: Axle and brake help
 

I got off the phone with Dana/Spicer about an hour ago and here is the info that was provided to me: The axle currently under my truck is a 68-71 M300/ D300/ W300 possibly out of a motorhome or 1 ton truck/ Van. Napa doesn't have brakes for ANY of those applications... Nothing even listed. Everything I find online is not like what was in there and I can't find what would/could have been original (schematics or even pictures of any kind). It currently has 13x2.5 shoes and rotors from Durabrake... That is all I've got...

Re: Axle and brake help
 

Maybe some help on RV forums?

Re: Axle and brake help
 

this is another 13x2.5, maybe the right hole pattern. P/N from Rock looks right
https://www.autohausaz.com/pn/CE-111...YLFwx24nYcGPEa

Re: Axle and brake help
 

Those do look very similar, thank. I will research these ones too

Re: Axle and brake help
 

So it took what seems like forever... But I think I've finally got this figured out. The only logical thing that I can see is : at some point something damaged the outer housing of the original axle and it was replaced with what was available, which happened to be a dodge axle housing. And either then or later someone swapped the brakes and couldn't find the correct parts. At that point the "redneck engineered" their own solution which wasn't a good idea. So the basic setup was 13" drum and shoes. I have so far replaced everything besides the backing plate(still waiting on a few parts) but I will include a parts list in here. Hardest thing to find was the wheel cylinders (kinda hard, just took more leg work than it should have) and the self adjuster "kits"(you can find the springs and adjuster itself, but hard to find the adjuster "lever" in a kit or separately). Most parts were available on RockAuto but their shipping costs are high and I was trying to source local.
Brake Shoes: 451(many retailers ad a set of letter before or after, but they are all the same)
Wheel Cylinders:AcDelco 18E771 & 18E772 or Dorman W9344 & W9345, 1.25 bore size
Parking Brake lever ("arm" internal): GM 15594177 & 15594178 (Good luck finding "78" it is discontinued)
Self Adjuster Kits: Carlson H2574 & H2575 (Dorman kits no longer contain the lever/"clicker" for the adjuster)
Spring/ Hardware kit: AcDelco 18K1598.
if you need it the parking brake spreader bar will probably have to be sourced from a salvage yard, both of mine were intact and could be reused. Oh and my drums look great, didn't even need to resurface, just cleaned. Thanks again for the help.

Re: Axle and brake help
 

That sounds like a real pain. Nice work finding everything. You are more patient than me. I would have tried to find a square body 1 ton 14 bolt FF and swapped it in. That 70 is a strong rear it should do you good. Are you running duals still or is it converted to srw?

Re: Axle and brake help
 

Going to run the duals once I get it back on the road. Generally because it is easier than trying to convert to SRW or finding some super singles the correct size, also my current axle is a 35 spline. I did find a 74 14 bolt that would probably have worked, I was just worried about internals on it because when you turned the yoke there was a mild grinding noise and feel. May have been just the yoke bearing... May have been worse, for 1k it wasn't worth the risk. Thanks for the encouragement, this one definitely had me running in circles for a minute.

Re: Axle and brake help
 

Yeah I don’t blame you. A grand for a 14 bolt of even pristine condition is way way too much. They are generally $2-300 at very most around here. Definitely not worth taking the risk. I’d be interested in seeing the continued progress on your truck. I love the 67-72 K trucks. They are the best looking trucks GM has ever built.

Re: Axle and brake help
 

I think I can do that. 👍

Re: Axle and brake help
 

Ok guys... In the continued saga of my rear brakes.... I put everything back together like the service manual showed... This axle has 13" drums, I've bled and bled and vacuum suctioned and bled again... When I got the truck the reservoir for the rears was bone dry, I assume because both of the wheel cylinders were leaking. I've bled brakes before a number of times... This one has me confused. I bleed and still have what seems to me as bubbles. I'm not sure where else to go, I tried adjusting the self adjusters till the brakes just barely contact/scrape, but I'm not sure how far to go. They do turn easier going backwards than forwards and I hear scraping. The brake pedal is medium and goes to the floor. The front brakes (I know are on a different reservoir) will lock up if I jam on the brake pedal. This truck does have a "Kelsey Hayes" hydraulic trailer brake attachment, Which could potentially be where air could getting in. Also when someone else is applying the brake pedal and the lid is of the master cylinder brake fluid shoots up and out of the master cylinder (I've never had that happen in any of my other vehicles... Newer or older). My only thought is my proportioning valve is bad, pushing the "button" on the front of the valve does nothing either.

Recap: 1971 GMC K2500 with a Dana 70 dually rear end and 13" drum brakes.
Disk/drum setup
front work fine
Rear I replaced/restored to GM factory 13" setup (2/3s of it was missing)
tons of bubbles when bleeding the rear cylinders but no visible brake leaks anywhere between MC and rear wheel cylinders.

Please any help would be greatly appreciated I'm ready to set fire to the whole kit & kaboodle.

Re: Axle and brake help
 

Continuing the "saga" my proportioning valve was so gummed up with crud it was stuck tight, should I try to source a rebuild kit for the original or just buy a new "PV2" version? Also if I'm going this far should I just spend the next $100 and buy a new M/C while I'm at it?
Also just ordered new SS lines from Inline Tube, they were super nice and had exactly what I needed in stock!

Re: Axle and brake help
 

I have no experience with them, but I have seen a lot of bad reviews on the brass PV2 valves. I would rebuild yours if you can. The are not complicated.

Re: Axle and brake help
 

I will try and get a picture in N a minute but... That thing looks like someone dumped a swamp in the the insides and I can't get the "valve" to move even after disassembling what I can. If anyone has a rebuild guide... That would be greatly appreciated too. What about the M/C? I (re) bled it after taking the proportioning valve off and the reservoir for the rears doesn't really build pressure... I can put my thumb over the bleed hose and fluid just squurts/sprays out of the reservoir (reverse flow).

Re: Axle and brake help
 

The master cylinder has to be bench bled. You are not trying to bleed it on the truck are you?

Re: Axle and brake help
 

I thought you meant was I trying to find a reason to buy a new one... I've always bleed them on any truck I've owned.. Honestly not sure what difference is, in or out of the truck makes if reservoir(s) are level and you can easily pump the cylinder till the bubbles stop. Educate me...

Less worried about that and more interested in why the fluid is shooting out of the orifice where it normally pulls fluid in AND why it doesn't pressurise enough to push my thumb off the bleed hose.

Re: Axle and brake help
 

Regarding the combination valve, I sent mine to White Post Restorations and had them rebuild it. I preferred that compared to going through hit or miss on chinese all-brass valves that are common. I re-read the thread and I don't see mention of your rubber brake hoses, how old are those?

Re: Axle and brake help
 

About a week old... I just swapped all three when I did the rear drums, mainly because I was already there and they are cheap and easy. I wasn't sure how old they were and they were caked in dirt and grease kinda figured they probably already collapsed.

Regarding everything else.... I've decided to just send the whole kit in to White Restorations. Final straw was when I cracked loose one of the nuts for the M/C on the booster and got sprayed in the face with brake fluid under pressure. About a cup of fluid leaked out over the next few minutes... So yeah whole new setup for me. Anyone know the part number I'm looking for, for that 1 ton vacuum booster? Possibly a source or part number for the M/C depending on what White Resto tells me on Monday? I've already got a quote on the cast iron proportioning valve, forgot to ask about the M/C and didn't know about the booster at that time. Thanks again everyone.

Re: Axle and brake help
 

Every master cylinder I have ever replaced, the instructions said to bench bleed the m/c. I never tried to bleed it on the truck.

Re: Axle and brake help
 

At this point it is negligible either way (not trying to be rude I promise) I cracked loose the bolts holding the M/C to the booster and got pressurized brake fluid to the face(good thing I wear glasses)... Found out where all the pressure was going *facepalm* and didn't even realize that it was leaking into the booster, so I will be sending off the proportioning valve to White Restorations and hunting for a new booster and M/C. From what I can find the master cylinder that I currently have is NOT the original as it is stamped "made in China" and it looks to be the "Moraine style"? There was a different kind(style) M/C in the floorboard when I got the truck that has an AcDelco P/N. I've found both of those at Napa near me... I'm not exactly sure how to make sure they are what I'm supposed to have but I'm going to give them a shot, fittings seem to be correct but bore size on Moraine style is 1-1/4 and this one is 1.125 (1 1/8?). I can't find anything on stroke length for either of them.

NAPA P/Ns: Brake booster - NBB 5471007
Master Cylinder - NMC M36246

Re: Axle and brake help
 

No offense taken, I’m glad you found the issue. If you use the search function you will find many threads on this subject.

Re: Axle and brake help
 

I have, but there are a few threads saying different ppl have used either, the booster is correct. I'm not sure exactly which Master Cylinder to use yet I've got it down to 2 different ones.

P/Ns : M2085 (Moraine style) it was on the truck
Or : M36246 this is the one that was in the floor board.

Now remember this truck has a 1 ton Dana 70 dually rear axle with 13" drum brakes.

Any help or advice would be greatly appreciated.

Re: Axle and brake help
 

Either style booster should work as long as the correct master cylinder is used in combination. Having said that, I can’t say which master, as I have no experience with 3/4 ton trucks. I’m sure someone will chime in with the answer.

Re: Axle and brake help
 

Hope fully *crosses fingers*

Re: Axle and brake help
 

A thing to watch for when you buy the new master and booster is the depth of the hole in the master cylinder piston. Don't remember which gets deep, or which get the shallow hole, but if you have it in your hand, it'll be an easy check, and an obvious difference. Should be OK because you aren't changing out the bell crank behind the booster, are you?

Re: Axle and brake help
 

I was not planning on changing that or messing with it at all to be honest. Thank you for the heads up on the depth.

Re: Axle and brake help
 

So Update...got all the old parts off, the booster was almost full of brake fluid �� I got a new brake booster and "Moraine style" master cylinder (Napa part M2085, new), already "bench bled" the master. Got them all pretty and installed today, waiting on my new Stainless brake lines (Wednesday) and sent my proportioning valve to White Post Restorations. Might not see the valve back for a few weeks but it is totally worth it to have the right part, repaired correctly, with a lifetime warranty... ��I'll keep you guys posted on how it goes. Thx again for all the help.