1948 KB5 Railway Express


The place to put your K or KB "Build Off" story.

Site Admin
Site Admin

Posts: 4930

Joined: Thu Nov 29, 2012 9:10 am

Location: Nampa, Idaho

Post Sun Aug 16, 2020 6:25 pm

Re: 1948 KB5 Railway Express

Look good, hope they work the first time.

Golden Jubilee
Golden Jubilee

Posts: 358

Joined: Sun Nov 15, 2015 8:16 am

Post Sun Sep 06, 2020 4:11 pm

Re: 1948 KB5 Railway Express

I enjoyed reading your very descriptive blog in this forum. A ton of fine, detailed work and may I say great, great patience.

BK

Golden Jubilee
Golden Jubilee

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Joined: Thu Dec 27, 2012 12:45 pm

Location: Canada's left Coast

Post Sun Sep 06, 2020 6:04 pm

Re: 1948 KB5 Railway Express

FANTASTIC !!!
I would rather have tools I do not need than to need tools I do not have
“Never argue with stupid people, they will drag you down to their level and then beat you with experience.
Mark Twain

Yard Art
Yard Art

Posts: 96

Joined: Mon Sep 04, 2017 6:22 pm

Post Sun Oct 11, 2020 9:33 pm

Re: 1948 KB5 Railway Express

Thanks for the support. I have not gotten around to the rear brake install as the heat & humidity was kinda high here in NC and couple that with hungry mosquitoes, I just stayed away from working on the truck.

I am back tackling the rear brakes as it has now cooled. I placed the steel shoes up into place just to see if they were going to fit or if I was going to have to make modifications. Amazingly,the fit like originals.

So I began to remove the adjusting cams that the brake shoes set on and are used for brake shoe adjustment. I had a problem with the top front cam which has a "triangle" plate that rotates and sets into a flat notch on the brake shoe. See No. 16 in the illustrated brake drawing. Not sure why it is designed this way. Anyway, on the back side is the 15/16" nut that tightens it to the backing plate and it was frozen solid. Used a little heat and hit it with PB Blaster and did this a couple times with no movement. My standard 6-point socket was too short to get a good bite on the nut and I did not want to get crazy putting a ton of pressure on the breaker bar and round off the nut. I needed a deepwell socket which a guy at work had. The nut sat a week with the PB Blaster coating it and I went out today and slipped the deepwell socket on and this time used more force on the nut and it broke free. It was raining here all weekend, so I returned into my house knowing I can remove the adjusted another day.

The original cast iron shoes are held into place on the backing plate by a long fine thread bolt which passes through an oversized hole in the shoe. See No.'s 6,7,8,9 in the illustrated brake drawing. Each side of the shoe is raised about 1/2" where this bolt passes through and can be seen in the drawing. The replacement steel shoes are of course flat. I did not like the double nutted bolt idea and decided to use a little more contemporary set-up. I was able to use the hold down pin, springs, and hat from a 1960'-70's Pontiac drum brake - Photo 1. I had a kit hanging around and tried it and it fit. You will see the pin which first passes through a large fender washer and then passes in from the back of the backing plate. The pin then passes through my steel brake shoe hole. The Pontiac brake shoe has a "hat" with a flared end that sets down into a sized hole on the shoe and is seen in the photo, but the hole in the KB shoes is much bigger so I got a washer that the flared end of the hat fits into and then sets over the shoe's hold down hole. This actually allows side movement of the spring in the same manner the factory bolt has side movement through the oversized hole. Then the green spring fits into the hat and over the pin. Then the green spring is compressed to install the top hat that locks everything together - just like the drum brakes on an older car. I purchased another set for the other side when I get to it.

Next up was the replacement of a broken brake shoe spring. If you look at the brake illustration, the broken spring is No. 4. Working at a big rig trailer shop, I was able to match up a brake spring that looked close, but had different ends. The trailer spring also has a slightly larger wire diameter and is a slight bit shorter in the coil winds - but I think it'll work OK as the tension both pulling and bending the spring seemed to me about the same. I rigged up a piece of small round steel bar I had and clamped it to a vice. I then heated the end hooks with my torch, putting pressure on the hook with pliers to get my bends. I heated the wire just enough to get it into a state of "soft plastic" and formed the end hooks around my steel bar to get the shape I needed. Then I cut the excess from the formed hooks off with my die grinder and cut-of wheel. Pic 2 shows the factory spring at the top, the middle spring is what I made, and the bottom spring is what I started with.
Attachments
KB5 Hi-Tork Rear Brake Assembly.JPG
DSCN0397.JPG
DSCN0398.JPG

Yard Art
Yard Art

Posts: 96

Joined: Mon Sep 04, 2017 6:22 pm

Post Sun Oct 25, 2020 3:14 pm

Re: 1948 KB5 Railway Express

And another rainy day to screw up my weekend working outside on the truck. So got some inside brake work done.

[b]KB5 Rear Axle Felt Seal Replacement How-To[/b]

The 1948 KB5 box truck rear axle uses felt oil seals as opposed to the modern lip seal. My felt seals were worn on one side and looked to have been replaced on the other side. Trying to find a felt seal to replace mine proved to be futile. Hmmm, NAPA just didn't stock them. LOL

So my option was to make the seals myself. Never did this, but did a little researching and found some articles on cutting out circles in cloth and other paper materials for home crafting. Compared different circle cutters. So had an idea of what I needed to do. Here is what I did and you may have your own way as well.

The KB5 axle uses 2 different means of felt oil seal application. The inner seal goes behind the bearing and race and sets inside the drum. It is a sandwich deal with a large flat round steel washer on the outside of the felt seal which the axle passes through and the felt fits snuggly around the axle tube an inner lip of the rear drum.

Pic #1 - The outer felt actually sets into a groove/channel on the backside of the axle nut that holds the brake drum on the spindle and rests up against the axle flange to create the seal.

I measured the larger inner felt oil seal and is 4.50" OD x 3.25" ID x .40" thick. The smaller outer felt oil seal measures 3.12" OD x 2.62" ID x .40" thick. This may not be 100% accurate as I do not have any specs or old catalogs giving me dimensions.

I could not find any category F5 dense felt material used for oil seals that was .40" thick - 13/32. What I did find was the needed type F5 felt at Grainger in a 12" x 12" sheet. I purchased a sheet of 3/16" thick (6/32 - $10.66) and a sheet of 1/4" thick (8/32 - $13.49) that when combined together put me at 14/32nd, which was close enough and the felt will compress.

Next I purchased a circle cutter, NT Cutter C-1500P off Amazon for $27.07. Simple to use and pretty straight forward. The tool has a pin on the bottom that can be used to spot the cutter. I placed a dot on the felt and lined the pin on that dot so if I had to move the cutter, the dot would be my reference point to go back to. Just make sure you have enough edge for the outside cut and don't go off the felt - you want to do your inner cut first, then the outer cut.

When you make your cuts, you will use the radius dimension of the felts, not the actual inside & outside diameters. Since I had to divide my felt sizes in half to get the radius', I decided to convert inches to millimeters which is just a click of a button on my digital micrometer. I also wanted to go a little larger on the OD and a little smaller on the ID assuming that compression/wear may have changed the actual sizes. For the larger oil felt I went with an ID of 40mm (half of 3.25" is 1.625" or 41.2mm) and outside diameter of 58mm (half of 4.50" is 2.25" or 57.15mm). I could have just as easily used the inches and added a little to the OD and subtracted a little from the ID - its just how I did it.

Using my micrometer, I first make my inside diameter cut which was 40mm, and adjust my micrometer to 40mm and lock it down. Then I use it to measure the distance from the center pin on my circle cutter and the small cutting blade. The arm the blade is attached to slides in and out, so I got my distance of 40mm and then locked the cutter into place. The cutter blade can be adjusted for thickness of materials, so adjust the length of the blade slightly more than the thickness of the felt being cut.Then set it on your reference dot holding down the pin on the felt using thumb pressure on the cutter's hold down knob, and slowly work the cutter knife blade around in circles using only a little pressure and letting the blade cut through. Once cut, leave the cut center in place as you need this position the pin on the cutter. Then adjust the blade arm to the OD of the felt seal (58mm) using the micrometer, tighten it down, and place the alignment pin back on your dot and cut the felt. Once cut, then you can seperate the felt seal parts. If you did not cut all the way through, keep the felt center in place, and put your cutter back on and re-cut. I had to drop the blade a little a couple times to get all the way through.

You will want to make 2 felts to match the factory inner oil felt thickness. So cut one felt in 1/4" and another in the 3/16". I will lay them on top of each other and put a couple dabs of sealant on them just to keep them together when I install them.

You can test fit the felt seal on the axle to make sure it is snug and test fit it into the brake drum to make sure it is snug. I actually had to make a couple felts before getting it right - a learning curve. So if you have to adjust your cutting ID & OD numbers, do so.

I did the same thing for the smaller seal for the outer bearing nut and used the thicker 1/4" felt. Again, I went with millimeters, 33mm for the ID cut and 40mm for the OD cut. When I inserted the new felt seal into the spindle nut groove, it extended enough out that I can just use the 1/4" thick felt and not add the 3/16" felt with it. I will put a small layer of oil resistant silicone behind the felt when I am ready and then install the felt and let the axle flange set the felt depth were it needs to go.

Felts get oiled up before installation, they don't go in dry.

Picture #2 shows the felt material, NT Cutter, digital micrometer, the spindle nut with my new felt seal installed, original seal below it, and my new felt seal for the other drum. Next to that is the inner bearing seal and how it is a sandwich type set-up with the original felt in the middle, and an example of my new felt seal above it.
Attachments
03.JPG
01  KB5 Felt Seals.JPG

Site Admin
Site Admin

Posts: 4930

Joined: Thu Nov 29, 2012 9:10 am

Location: Nampa, Idaho

Post Sun Oct 25, 2020 8:27 pm

Re: 1948 KB5 Railway Express

Love your work, making something for your truck can bring satisfaction. The How to should help others.

Yard Art
Yard Art

Posts: 96

Joined: Mon Sep 04, 2017 6:22 pm

Post Thu Nov 12, 2020 7:29 pm

Re: 1948 KB5 Railway Express

Had a good weather weekend, so got some time in on the KB5 rear brakes. I got all the brake adjusting cams/hold-downs for the brake shoes off the backing plates. They use a 15/16" nut with the top adjuster needing a deep well socket to get it loose/off. I did not want to use a box wrench on the nuts because these things were frozen tight with rust and undercoating that someone put on them - if they rounded off, I would have had a bigger job in getting things apart.

Pic #1 shows all the adjusting cams/hold-downs and pieces, and going from left to right in my description. On the left is one style of adjusting cam. You can see at the bottom looking straight at it is the end of the threaded bolt - it has a hex key used to turn the cam adjuster after you loosen the 15/16" nut so you can turn it. It is what goes through the brake drum backing plate and you see on the outside of the backing plate used for adjustments. This rotates the cam which causes the brake shoe itself to move outward or inward against the brake drum. Above that is the brake shoe side of the adjuster cam that one of the alignment holes in the the brake shoe fits over. You can see the shape of the oblong cam being offset more towards the bottom as measured by the circular end cap. That round machined end cap has a groove cut into it for a horseshoe clip which when installed, secures the brake shoe from slipping off the adjuster. Above that is a thin metal cup/cap that is shaped and fitted to go over the 15/16" nut on the backing plate to keep water/dirt off the hex key and threads. I had to chisel into these to cut into them and pry off. I have some rubber replacement caps used to protect the ends/threads on hydraulic fittings that are the perfect fit and will be used.

Next to that is same adjuster looking down at it from the side. The smaller diameter rounded end is where the horseshoe clip gets installed into a machined groove. Next you can see how thick the actual cam is that goes through the hole in the brake shoe. The shank goes through the brake drum backing plate, and then a flat washer and lock washer gets installed and then the 15/16" nut onto the threads. The threaded end has the hex key and by turning it with a hex wrench, you adjust your brake shoe clearance with a feeler gauge which gets inserted through a slot in the outside of the brake drum. Once adjusted up, you tighten the 15/16" nut down to cinch things into place. Pretty simple as I did the front brakes like this.

The next adjuster is different and is found at the top front shoe. Looking straight down on it you can see how offset the cam's pin is. This gives a lot more adjustment than the other style cam adjusters. This pin has that triangular block fitted to it with a horseshoe clip. The triangle is free to rotate and its flat edge fits right into a flat/straight edge found on the brake shoe. It has a machined taper on the inside that fits over the pin which has a slight flare at its base - and can't really be seen in the photo. Next you can see the tapered shank. This fits into a machined fitting that is fixed into the brake backing plate. I assume the taper is used to allow for a really tight and perfectly aligned cam adjuster so as to fit exactly in line with the flat edge on the brake shoe. The shank goes through the backing plate, has a flat washer and lock washer and 15/16" nut. However, the threaded end adjustment does not have a hex key, but a small extended tip having flat sides to it that can be adjusted using an open end box wrench or adjustable wrench. This is like what the front brakes use.

Next to the exploded cam adjuster is the adjuster with its triangle block still attached, and the flat washer, lock washer, and 15/16" nut that is on the backside of the brake backing plate.

So you have 2 identical brake shoe cam adjusters and 1 triangle brake shoe adjuster per side. I will clean them all up and make them ready for re-installation. Did a little more other brake work, but am waiting on some parts to finish what I did and will put it up as completed section as I have done here with the brake shoe cams. This is really slow going and step-by-step. I find myself doing a lot of internet searching trying to get just the right part that I can modify for use on these old brakes - I don't know if I have more time working on the brakes or the internet. LOL Then I have to wait for the parts to ship/arrive and then I can begin making them work. Why couldn't this have been a 1970's Chevy C-10 pick-up where I could just order my parts from a catalog? LOL

Pic #2 is a better close-up of the brake cam adjusters and Pic#3 is the rear brakes diagram so you can better see where these go.
Attachments
01  KB5 - Rear Brake Adjuster Cams.JPG
02  KB5 Rear Brake Adjuster Cams.JPG
KB5 Hi-Tork Rear Brake Assembly.JPG

Golden Jubilee
Golden Jubilee

Posts: 4654

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Fri Nov 13, 2020 9:38 am

Re: 1948 KB5 Railway Express

mrjim2017 wrote: Why couldn't this have been a 1970's Chevy C-10 pick-up where I could just order my parts from a catalog? LOL

Simple answer, you are not dealing with light vehicle brakes. You have foundation brakes like most all heavy vehicles use. Light vehicles don't have the bottom of the shoe a fixed to the backing plate, rather the two shoes are tied together with the adjuster. This means all force on the shoe is applied to the wheel cyl, which must transmit it to the fixed backing plate. With heavy vehicles that wouldn't work.
The two adjuster (major and minor adjustments) with bottom of the shoe fixed to the backing plate, has been common right up into the 70's. In short, it is the difference between working on a light or medium/heavy vehicle.

Yard Art
Yard Art

Posts: 96

Joined: Mon Sep 04, 2017 6:22 pm

Post Sat Nov 21, 2020 4:30 pm

Re: 1948 KB5 Railway Express

This brake set-up does no use a brake adjusting cam on the lower back shoe, only on the front shoe do you see this. The brake adjuster with its star wheel pushes off the front shoe to become the way in adjusting the lower part of the rear shoe. The front brakes do have adjusting cams top & bottom which the shoes attach to with the cams being attached to the backing plate. This brake system is odd in the sense that you have 2 brake cylinder pistons, the larger one that pushes against the front brake, and the smaller piston found in the "leg" of the brake cylinder that pushes the rod attached to the brake adjuster. The front half seems more on the line of "normal" hydraulic brakes while the rear half seems to utilize hydraulic & mechanical leverage combined. Would have been much simpler if it had air brakes and S-cams.

Moving forward - My KB5 rear brake assembly uses a brake adjuster having a star wheel that adjusts it. The left side brake assembly was broken with the front cast shoe in 3 pieces and it must have broken the star wheel from its adjusting pin. Only half of the star wheel was present in the base of the brake drum when I removed it.

I had to fabricate a new star wheel using the broken half as my pattern and matching the good one from the right brake. I measured the star wheel with my micrometer which was .154" thick, had an OD of 1.5", and the pin it was attached to had an OD of .75" making the ID of the star wheel .75". I got online and found a military grade 18-8 stainless steel washer that had a 1.5" OD, .75" ID, and was .160" thick (Perfect!) offered through RAW PRODUCTS CORP, and purchased on Amazon. I had to buy a package of 25 to get the 1 washer, LOL, but knew I was getting the dimensions I needed versus going local with my micrometer and driving around store-to-store looking for a match.

The washer arrived and it was a perfect fit. I measured the broken star wheel's "teeth" and found that they were tapered being .30" at the top tapering down to .28". I drew out a pattern on paper using the center of the hole of the washer as my measuring point. The cut outs between the teeth was 1.15" inch diameter and dividing this by half to get a radius from the center point, I adjusted my compass accordingly and made an inner circle which was the 1.15" inch diameter. The OD was 1.5", so adjusting my compass for its radius, I drew the outer circle of 1.5". I then marked on the outside circle increments of .30" which were the width of the teeth at their tops. Then using my center point, drew a straight line from center point to each mark on my outer circle which gave me equal spacing of all the star wheel teeth. I then filled in the teeth with a Sharpie leaving the spaces inbetween that would have metal material removed to make the star wheel teeth. This sounds more complicated than it is, but making this drawing is what I used to mark up the washer in making the star wheel teeth and where I was going to have to grind on the washer. Picture #1 is the drawn pattern.

Next I laid the washer on top of my drawing and marked the washer with my Sharpie following the lines on my pattern to mark the teeth and those spaces inbetween that I was going to have to grind out. I then colored in what would be the teeth leaving blank the spaces inbetween. I now had a pattern on the washer that I was able to work with in cutting the star wheel teeth.

I used my small hand held electric grinder with its 4" steel grinding hard disc to rough cut the teeth. I think the disc is about 1/4" thick. I used the edge of the disc to cut into the washer and grind out the metal between what would become the star wheel teeth. The grinding wheel is not exactly square on its edges, so I kept it centered between what would become the teeth and ground down almost to the inner 1.15" diameter inner circle line on the washer. I went all around the washer grinding the metal out and making my rough cut-outs. Then I followed this up with my high speed die-grinder and cut-off wheel and dressed each of the ground out areas to bring the cut-outs closer to the edge lines of the teeth. I found that I could use a 1/4" drill bit shank as a guide in telling if the cut-out space was wide enough between the teeth. This got them all equalized. Then I followed this up with a little dressing with a hand file and rounded the sharp edges found at the top of the star wheel teeth to match more closely the original star wheel. This completed the new replacement star wheel.

My next problem was the fit of the new star wheel over its pin. The ID of .75" fit perfectly, but the pin used a hex shaped center that the original star wheel matches on its ID. It also appeared the star wheel was swedged on the pin. I ground down and rounded the swedged and raised areas of the pin smooth so the new star wheel could slip over it, but I left the back half of the swedged/raised area as a stop. This worked perfectly for fit. I then welded the new star wheel to the pin to secure it in place.

The star wheel adjuster was now as good as new and will work as factory.

Pic #02 is the good brake adjuster and star wheel on top. Underneath it is the adjuster with the star wheel/pin end removed from the threaded screw it attaches to. Looking under that from left to right is the original broken star wheel, the stainless steel washer I started with, the new fabricated star wheel, and the pin it fits on to and where I ground it down for fit.

Pic #03 is a closer look at the parts.

Pic #04 is the original star wheel from the good brake adjuster.

Pic #05 is the new fabricated star wheel welded on the adjusting pin. You can see a little better the "V-shaped" spring lock at the top of the star wheel that locks the adjustment in place. Lift it up off the notch, rotate the star wheel cogs to adjust the brake clearance, and then drop the spring lock back down into a notch to secure the adjustment.
Attachments
01 Star Wheel Pattern.JPG
02  KB5 Rear Brake Adjuster.JPG
03  KB5 Rear Brake Adjuster.JPG
04  KB5 Rear Brake Star Wheel.JPG
05  Replacement Star Wheel.JPG

Golden Jubilee
Golden Jubilee

Posts: 4654

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Nov 21, 2020 7:15 pm

Re: 1948 KB5 Railway Express

Again, these are very common in medium and heavy trucks. the same system was used in the K series larger trucks.
With heavier trucks, the shoes need to transmit the torque to the backing plate and not the cyl like most lighter brakes do.
My K'7's use the same system. It may be new to you, but foundation brakes are not new or unusual.
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