Have brake pedal after a couple pumps!

[hugger94]

This is the information I believe to know about this dump truck:

1975 loadstar 1700 single axle dump truck
2 wheel drive
manual transmission
345 v8
Holley 2bl
list 2980 284546-c91
451
cast iron Holley distributor “1510” with gov. And tach (not used)

-------------------------------------------
new information:

brake master cylinder – single reservoir with a single diaphragm booster located under the driver running board.

I have bled the bleeder screw on the top side of the brake booster under the drive running board, (it looks like a slave cylinder). I have been able to bleed both back brakes by breaking loose the brake lines and was able to break loose the passenger front wheel brake line on the back side of the wheel. This loadstar has two wheel cylinders on each front wheel. All four bleeder screws on the front wheels are frozen and will not give. I wasn’t able to break loose either of the driver front brake lines.

I do have some pedal now after this attempt when I pump the pedal a couple of times. I am now looking to replace the wheel cylinders on both front wheels to make sure I can bleed the brakes. I am being told that I need to determine the axle code and whether or not I have 15 x 3 or 15 3 ½ brake shoes to determine which wheel cylinders I need.

Can you help me locate the axle code? Please don’t tell me to look on the vin plate because this vehicle has been given a kansas re-assigned vin# because it was wrecked.

I would greatly appreciate any assistance you can provide.

Hugger94

 

[RobertC]

The axle code is on your line setting ticket (LST).

Available from IH vendors or wisconsin historical society.

http://www.forums.IHPartsAmerica.com/basic-tech-questions/3995-line-ticket-location.html

But, since this is a "salvage" vehicle, the front axle May not be the same one put on at the factory...

I think you need to pull a drum to actually find out what size brake shoes you have.

 

[Michael Mayben]

No need for a lineset or an axle code to determine which brake set you are dealing with.

Because the brakes May have been previously worked around (very common on these trucks), you need the numbers that are going to be cast into the wheel cylinders for matchup. And a brake shop or friction materials company that deals in the hd market will have 'em on the shelf.

Same for the brake shoes, in the truck bizz, we don't replace the shoes with over-the-counter crapball "bonded" shoes, we have the takeoff shoes relined correctly using a riveted lining material, or the truck parts house will have proper riveted shoes on the shelf for exchange.

By bleeding at the line, ya still have all the air trapped in the wheel cylinders.

For removing frozen bleeder nipples, number one, you are going to waste 'em. But so what, they need to come out anyway and be replaced with new.

I don't fight frozen bleeders at all, you will never win. I clamp a pair of appropriate vise grips on the remnants of the bleeder hex, then use a propane torch to heat the area where the nipple threads into. That expands the cast iron cylinder just enough to allow the nipple to break loose. Penetrating lube normally does not work on these as they are seized on their sealing taper, not the threads.

Once ya have the brakes torn down and the wheel cylinders off for inspection, replacement cups are easily sourced.

Is the brake shoe adjustment mechanism an eccentric cam-type or does it have a star wheel? If it's a cam-type adjuster are there one adjuster or two? If it's star-wheel adjuster is there only one adjuster or are there two?

From that point we can determine if ya got single push wheel cylinders or double push. I have the service manual for this vehicle but I do not have the parts list here.

By far, the best way to make positive id of this stuff is pull the hubs/drums and look! To service the wheel cylinders they have to come off anyway.

 

[hugger94]

Michael,

thanks for giving me some hope that I can get brake shoes and wheel cylinders for this beast…

yes, I know that air is still trapped in the wheel cylinders and that’s why I am trying to get the bleeder screws out and replaced. When I started this part of the project, I had no pedal what so ever and after bleeding at the brake line input to the wheel cylinders starting at the passenger rear I am able to get enough pedal after pumping the pedal a couple of times to stop the truck.

I have tried both vice grips and a craftsman “bolt out” but neither broke them loose.

I have taken a few pictures to show the back side of the driver front wheel. Pictures labeled dscn0483.jpg shows apparently the cam bolt on the bottom of the hub.
Dscn0484.jpg shows the front bleeder and brake line going up to the top brake line splitter.
Dsnc0485.jpg shows the other cam bolt I’m assuming.
Dsnc0486.jpg shows the rear brake line coming down to the rear wheel cylinder.
Dsnc0487.jpg and dsnc0488.jpg shows the brake booster under the driver running board as well as the “slave cylinder” which I bled at the bleeder on this cylinder.
Dsnc0490.jpg shows the brake master cylinder with the id numbers on the side.
Dsnc0489.jpg shows the driver front wheel.

I am planning in the next week to make arrangements to take this loadstar to a friend’s house where we can work on it on pavement and not in the field.

Is there anything special to worry about removing the wheel and brake drum? I am assuming you need to remove the five lug nuts marked in the center to remove the tire. Then you would need to remove the center cap to get to the axle nut, etc.

I didn’t see any slots on the back plate so I am assuming the identified bolts at the top and bottom of the front backing plate are the cam adjusters.

As always I would appreciate any and all input.

Hugger94

 

[Michael Mayben]

Great pics!

So...ya have the brake system that uses the external "cam adjusters, one for each shoe.

This is going to be a mess to work with, but then most all old hydraulics on rigs like this are.

Gimme some time to work through the tearout on this for ya and I'll provide ya the appropriate service procedure. Dealing with this type wheel/hub/brake system is not like working on ihc light line stuff at all.

I'll be back with more info tomorrow!

 

[Michael Mayben]

Ok, we'll take this in stages since there are quite a few brake set "options" used on the loadstar series.

Using a cts 2300 (the big bible for ihc light/medium duty trucks), I think this scan pertains to the brake set you are working with on the front axle. There is one other possibility so let's make certain we're working with the correct system. These two pages will allow positive id, I have more scans but let's make sure we have the correct stuff here!

So check this out and let me know if I popped out the right scan, if not, we post the other possible.

As for pulling the hubs/drums, that is very straight forward and is done in the manner I think you are familiar with, just like on light duty/2 wheel drive systems. The service manual does not go into a detail regarding hub removal for the front axle, but quite detailed info on servicing rear axle stuff.

 

[hugger94]

Ok! I finally got the loadstar on some pavement so I could jack it up to take a front wheel off....

I started by putting an impact wrench on one of the five lug nuts identified in the wheel picture posted earlier. The nut turned hard at first then started spinning. When I removed the impact I found the stud was turning. I then put a breakover bar on the next one but after turning hard a couple of turn, it started turning as well.

I then removed the four bolts holding the dust cover on and took out the outer wheel bearing. I was unable to get the wheel and hub off that way. I am assuming that I will have to loosen the cam adjusters to release the shoes from the drum. Before I really get things in a mess, I thought I would ask there was anything special in releasing the cam adjuster? Assume you would turn them left or counter-clockwise.

Sorry to be such a pest, but this has really got me second guessing myself bigtime.

Hugger94

 

[Greg R]

You have a dayton or demountable wheel setup. The wheel comes off the center cast hub by removing the outer nuts that hold the rim locks on. The nuts/bolts you first tried turning are what hold the drum to the hub. The wheel by itself, let alone the hub with it, is a heavy sumbitch; so without a jack or some way to support, it would be almost impossible to remove the whole lashup by going the wheel bearing route without hanging up on something. My 1st choice would be to dismount the wheel, then work on the hub. The studs look like 5/8" or 3/4" , rusty, serious wrench'in there.
The cam adjusters are turned in the direction of forward wheel rotation to tighten things up. (cw on the driver's side, ccw on the passenger side). So the opposite of that would loosen things up.

 

[hugger94]

Greg,

thanks for the response and yes the nuts were 3/4. I had thought about the weight of the tire (it even looks heavy) and had planned to use my motorcycle jack to lower and raise the tire to remount it.

If I understand you correctly, if the inter five nuts that I started to take off first are removed the cast spoked hub and wheel would come off without taking the wheel bearing out? At this point about the only answer for the first two nuts are to cut them off with a torch or burp gun, the studs just spin as the nuts are frozen on at this point.

Hugger94

 

[Greg R]

No-o-o torchez
the drum is bolted to the hub, it comes off with the hub.
1. Remove wheel/tire from hub.
A. First loosen all the nuts and unseat the locks
b. Loosen the wheel from the hub, then remove the nuts and rim locks to remove the wheel.
(1) this step is a safe approach so you don't have the wheel unexpectedly falling off or on you!
2. Remove hub/drum like you would on another front spindle

 

[hugger94]

Greg,

are the five inter studs regular bolts or knerled studs that are pressed into the drum? Since I have never taken one of these wheels off... I don't know and have to ask?

You have convinced me to remove the outer lock/lugs first to remove the wheel from the spoked hub. Then loosen cam adjuster to allow the drum to come off the shoes. Remove the center wheel bearing and remove the hub and drum as one piece.

Sorry to be so dense on this but it really has me second guessing my self.

Hugger94

 

[hugger94]

Okay, I finally got the wheel and hub off this @#$#%$* thing after a lot of different attempts. The brake shoes were frozen in place, assuming that the wheel cylinders were dry hence I was unable to bleed them.

We tried to remove the outer lugs to remove the wheel first but my ½ drive impact would not even touch breaking them loose. Tried a break over bar with a cheater pipe still without any luck. The only way to get this driver wheel and hub off was to loosen the three bolts from the backing plate to give a little movement in the brake shoes, allowing us to pry the hub off with the wheel attached.

Once the hub was off, I saw what I figured was the problem. The wheel cylinders were toasted and hadn’t been working for quite some time. The brake shoes didn’t look that bad, I had already removed the upper shoe and both wheel cylinders to get the numbers off the cylinders before I took any pictures.

The front single action wheel cylinder pushes the bottom shoe downward against the bottom of the drum as well as serving as a solid stop for the front side of the upper shoe with the slot on the back of the wheel cylinder. The backside single action cylinder pushes the upper shoe upward against the top of the drum, again also serving as a solid stop for the back side of the bottom shoe. Both brake shoes are held in place by the single pivot of the cam adjust shaft and both springs connecting both shoes.

The slot at the top of the backing plate is where the bolt holding the “y” fitting connecting the brake line hose to split the brake line to feed both the front and back wheel cylinders. Once I had removed the upper brake shoe and loosen the bolt holding the “y” fitting I was able to get a 7/16 line wrench on the brake line at the “y” fitting to get it broken loose.

I was able to locate the correct wheel cylinders at the local parts house, raybestos wc37033 (left) & wc37034 (right). I am currently looking for the brake line hoses going out to the backing plate as the rubber is rubbing off on my hands.

Oh! The bolts holding the cast iron spokes to the drum appear to have a regular bolt head on the inside of the drum. I haven tried to tighten them but I would assume that I can or replace them if necessary.

I will upload pictures that were taken as an after thought covering my comments above.

Hugger94

 

[hugger94]

Ok, I finally got the front brakes (both side) rebuilt, including new wheel cylinders and cam adjuster kits, two per wheel. Before I start bleeding the system I guess I need to ask if there is a sequence that I need to adjust the individual cam adjuster on each shoe.

I would appreciate any advice before I go any further.

Hugger94

 

[Michael Mayben]

Stand by...I'm down with the flu right now and hardly coherent, but I'll scan and post the adjustment procedure once the drugs kick in.

I'm back temporarily...

Here's a scan of the front brake set I think you have, all the info needed should be addressed here.

 

[hugger94]

Michael, lol, I have time to wait.... Its only taken me over a couple of months to get this far, so a few more days won't matter.

The other scan you did was right on and was a very big help is doing this brake job. The second wheel went a lot faster once I figured out how to create pressure on the cam adjuster bolt, first to get the offset adjuster to stay in place on the slot while putting the brake shoe in place. Then again using a c-clamp once the shoe is installed to put additional pressure on the bolt to allow the final washer and keeper in place. I realize as I am typing this I should have taken pictures to show how I did it.

Oh well!

Thanks for your assistance.

Hugger94

 

[aaronp]

Where did you find that manual brake master cylinder? Have a 74 loadstar 1600 and need brake master cylinder?