The Stovebolt Site Forums The Shop Area Driveline Parking Brake Questions

Hello all,

My next project on my newly acquired 1950 Chevy 3100 is the parking brake. The brake doesn't work in two ways: one, when the pedal in engaged, it does not stay engaged; two, when engaged, the actual brake shoes are not (wheels still rotate).

I had some time this past Sunday, so I lifted the rear end and took a look. I was able to determine immediately that the cable mechanism is working. I then tried to adjust them and on one side there is room to adjust but the rust is so bad that the yoke or clevis won't rotate any further (I tried lube and a steel brush). I was able to adjust it a couple of rotations which was enough to stop the wheel from spinning, but I could still rotate the wheel by hand if I tried really hard. On the other side, it is at the end of its adjustment.

The pivot "arm" that both sides connect to has a spline on each end, so it seems that if the bolts could be loosened, one could rotate the connector on the spline to provide more adjustment. I'd rather not go this route because getting those bolts off is going to be difficult (rusted, tight space to work with) and I am guessing this is more about the cables just being old and stretched out.

So, I have no problem spending the money to replace the cables, I am just not confident when looking online that I am getting correct replacements. The closest to what I need seems to be:
PARKING BRAKE CABLE-1/2 TON

My main concern is that it lists it as 41 1/2 inches long which seems too long to me. From what I can tell, it should be about 36 inches long.

I've attached photos of each side.

Okay, the pedal engagement issue. I can't quite figure out how it should work. If I press the metal piece that the brake release is connected to, I can kind of get it to hold the pedal down, but it doesn't "stick". Is there something missing here? All I can think is that either something is worn or maybe there should be rubber grommet on it? I don't know. I couldn't find anything in the workshop manual.

So, any advice would be appreciated!

Thank you!

The hole that the rod goes through to hold the brake in the set position is probably wallowed out, preventing the pedal from holding. It works like the little sliding prop on the cylinder rod of a screen door.

I just looked at mine for comparison and you can't see any light or space between the pedal rod and the stop. Your hole looks slightly larger than the pedal rod.

Have you adjusted your brakes and parking brake as specified in the shop manual?

Also, are your drums new or worn out. They may be worn beyond spec for the brake to get a good grip.

I would expect most of your components are worn. They are 75 years old, after all. Might be a good time to disassemble it all and inspect everything. The rod from the pedal mechanism to the cross bar actuator, is multipiece. And, I think there is some adjustment in it, too. It's been a while since I had mine apart. You should also make sure your brake shoes are adjusted correctly. Cable replacement would be a good thing as somebody got in there and messed with one of them. The OEM clevis ends should both look like what you have in picture one.

Otto did a good job of describing how the pedal engagement works. It’s a goofy design, IMO, and if the hole gets wollered out and/or the edges of the hole get rounded off….it will have a hard time grabbing.

Mine only grabs if I push it like all the way to the floor. I’ve managed to live with it up to now, but it needs attention someday.

I have seen where folks file the edges of the hole to a sharper edge to restore the “screen door stop” action that Otto described. One guy on YouTube even added some weld and then filed to restore something closer to original geometry.

Something I’ve considered as a quick and dirty fix: filing a series of little notches in the pedal shaft. I’m not 100% sure if that would even work, and I’d need to study it a little closer to think about unintended consequences.

I did adjust brakes per the service manual before attempting to adjust the parking brakes. They seemed to already be adjusted correctly.

I will have to get creative with getting the parking brake release to work correctly. Thanks for the confirmation that is probably just loose/worn.

So, today I took off both wheels and the outer drum. On the driver's side, a small piece of metal just fell to the ground. After removing the other side I figured out that it goes on top of the slave cylinder and apparently the little screw that holds it in is AWOL. Otherwise, the driver's side looks pretty good to me.

The passenger side however was full of grease. At first I thought it was brake fluid leaking and making a mess, but it is grease/oil. It seems to be coming from what I can only conclude is a drain hole for the drive shaft which had a big glob in it, when I cleaned it out somewhat, it would drain gear oil if I rotate the hub so it is on the bottom. So, I can't determine from the manual what is supposed to be here. Is that supposed to be some sort of drain plug? There isn't anything on the driver's side and it is not leaking oil - though it does seem to have grease packed in it.

So, I need some help with how to deal with the hub drain hole (I attached a photo). The other photos of the brakes are after cleaning them up.

Thanks!

I looked at some pics of when I was working on the rear axle and brakes. I'm no expert, but it looks like if the axle seals leak maybe the gear oil gets directed to the outside of the hub, away from the brakes? But don't the drums cover that hole? Not sure how it works.

Edit: Looks like the rear drums do have a "drain" hole that should line up with the hole on the axel. Maybe it is a drain? I believe I ran a small wire brush through it to clean mine out before installing the axles.

I was afraid it would be a "weep" hole for when something is leaking. I am likely looking at something with the axle seal. I am going to have to do some research on where that seal is and how to replace it. This is all new to me, so any advice welcome.

Thanks.

lc_btv - Here's an on topic thread directly related to your situation.

Your axle seal on that side is leaking and you'll need to follow the process on page 4-3 through 4-5 of the 1948-51 Chevy Truck Shop Manual to pull your axle for replacing the seal.

Since you are already going to get into the axle this way, it may be best to to go ahead and replace both side axle seals, along with checking your bearings and replacing if necessary. You won't want to do the job twice if you don't have too.

Thanks for the link to that thread. More things to ponder and check. I have the 48-51 shop manual (came with the truck), and I have already looked through the pages you reference. Like the poster of the thread you linked to, there just was lot of steps and it didn't seem very clear to me how to get started.

For example, steps 6 and 7 under removal, involve removing a bunch of things in the differential, but I don't know the terminology. And then, like in the thread you referenced, there was all of the steps involving peening and oil deflector, etc. So, I was feeling a little overwhelmed.

As far as the bearings go, when I rotate the hub, it should be completely smooth, correct? Or, can there be some faint "grittiness" feel just from the driveline rotating? I can feel it a bit when I rotate the hubs and just want to make sure I am diagnosing it correctly. I may just go ahead and order bearings at the same time I order the seals.

Thank you for all your help!

Hy lc_btv and guys, it looks like the piece of metal that fell out of the drivers side drum is your adjustment "lock" spring clip from above your wheel cylinder, it doesn't look like the retaining screw for that piece is broken off as there appears to be a hole there, make sure there are still good threads in that hole to retain the adjustment "lock" spring steel piece. The replacement of the axle bearings and seal is a bit of a complicated job, but if you follow the manual it is doable, if you have trouble just take pictures of what has you baffled and come back here and ask questions, that is what we're here for, good luck.

lc_btv - This scanning (courtesy of theoldcarmanualproject.com) of an original 1952 Chevy 1/2 ton Truck rear axle overhaul manual gives step by step instructions for all the things you need to do in partially disassembling your rear axle to replace the seals and if needed axle bearings. Your axle shafts, bearings and seals are covered under Section 3a of the manual.

It has detailed pictures and descriptions that should give you what you need to identify all the parts/pieces and steps involved. Yes it's for a 1952, but everything in your 1950 axle is the same with the exception of your Huck brakes vs the Bendix brakes used in 1952. For Huck brake disassembly/reinstallation, refer back to your Shop Manual.

Let us know how things go and ask more questions if you need more help.

PS - You do not have to do a 100% complete tear down to replace the seals and bearings. Once you remove the axle C-clips, you can stop differential disassembly, remove the axles, remove/replace the seals (and bearings if necessary), then reassemble.

3B - You are correct about the spring clip which was installed on the other side, so i figured it out. I happened to have a little bolt of the correct size and was able to reinstall it.

Thanks everyone! I will tackle this soon.

I ended up doing the following:
- Replaced the right side axle seal (what an ordeal getting the old one off!)
- Cleaned up the brake drum and replaced the shoes (since the old shoes were full of oil). My Uncle must have known there was an issue because there was a set of brake shoes in the garage when I got the truck.
- installed new parking brake cables on both sides (the cable from the pivot rod back to each drum).

I have a couple of questions:
- When I went to drain the differential, I removed the fill plug first and some fluid came out. It seems like that wouldn't be possible?
- I am trying to understand how the axle bearings are lubricated. When looking at the rear of the axle/differential assembly, it doesn't seem like the fluid level would get high enough to lubricate down the axle. And the bearings aren't sealed in any way, so I am assuming they are completely reliant on the differential/axle fluid for lubrication.

Also, while troubleshooting the parking brake (it still doesn't "work") I noticed this seal on the drive shaft was not screwed in (see photo attached). I attempted to get it back on multiple times and was unable to get the threads to engage. I tried to clean both thread surfaces, but to no avail. I assume the seal sits against shaft coming from the transmission and not "inside" of it, if that makes sense? Anyway, I put the truck away to tackle it another day. But any thoughts welcome.

As far as the parking brake is concerned, there is supposed to be a two piece rod from the lever back to the pivot rod (which no one seems to sell anymore) and on my truck, the second half obviously broke, so a rod was jury-rigged in to its place. I am thinking there is just too much play there. I don't know.

I've wondered about the differential fill plug on my '46 being low. I had someone tell me that when you are driving a taking corners, the gear oil will travel up the tubes. I checked one of my old pictures and the cover seems to be correctly installed.

Some hopefully helpful response to your questions:

"- When I went to drain..." - Yes it is entirely possible for there to be too much oil in your axle. Usual culprit is a failed front torque tube oil seal (behind the front driveshaft bushings) that lets oil from the transmission migrate down slope in the torque tube to the differential housing. The fix is to replace the front torque tube bushings and oil seal, unfortunately.

"-Iam trying to understand..." - Here's an very old on-topic thread that sums up how the axle bearings get lubrication, without a lot of technical terms - lol!

"...I noticed this seal on the drive shaft..." - In looking at the picture, it appears your transmission is kinda sagging down just a tad, and is most likely causing the difficulty with getting the seal collar nut to thread back on. You might be able to realign the collar output tube by hand to realign. If not, I think if you put a jack under the transmission tailshaft housing (not the ball collar assembly) and gave it just a little lift, you should be able to restore alignment and thread it back on. Your transmission rubberized mount is likely oil damaged/compressed, causing this issue. Yes, the seal is compressed against the ball collar output tube to create the sealing effect. Once the collar nut is back in place, IIRC, you need to lightly stake the collar to help keep it from un-threading itself during driving. I had this problem on my truck, but didn't know about the "staking step" to help it stay in place. I must have put it back a dozen times.

Dan,

Very helpful as usual.

I went down the rabbit hole about the torque tube oil seal. It sounds like the best thing to do is to install an Okie Bushing With Seal which I found on Chevy's of the 40s here? Otherwise a more complete dismantling if the drive shaft/axle, etc will be required - plus I am not sure the availability of the seal and bushings?

From what I have read, it looks like the Okie install is not too bad, I hope?

I did check the transmission fluid and it was low. The shaft seal and excess oil in the differential also explains the axle seal leaking.

I noticed some distortion around the edges of the seal collar which after reading your reply makes me think of the staking you are talking about. Regardless, I will order a new transmission mount and hope that helps the situation.

I appreciate you helping with links to other posts. I find the search function not all that helpful; I find it gives way too many unrelated results to be useful. Maybe I am not using it correctly.

Thanks.

Glad the info is helpful!

You're correct that replacing the original bushings and seal with an "Okie Bushing" with seal unit is the way to go. Lots of folks have done them and there are many threads discussing how to go about it.

Here's just one example, but it's the best and most complete Okie Bushing Installation thread I found so far IMHO. Granted the original truck being discussed is a '46, but your '50 should be pretty much the same. One word of caution - the early 1950 model year was when a slight change in the front drive shaft bushing set up happened. Some early bushings are actually retained by dowel pins peened in place the same as 1948-49 models. Check out the Shop Manual on Page 4-5 and Page 406 as the diagrams and instructions will help you determine which setup you have.

Give this Okie Installation thread a read. From there, maybe you want to start a new thread to focus on the Okie bushing topic and ask related questions to help keep the discussion on one task.

Yep, I found that thread and I have read about the difference that occurred sometime in 1950. We'll see which version I have. Thanks!

My new Okie bushing was very tight. I had a machinist friend turn it down to match the old one I removed.