Trying to get it going and found this

[HRD]

Pulled the master cylinder off my 51 GMC that I'm going through checking just to get back on the road.
Truck was last tagged in 1969. I found it in a barn in the early 2000's. Had it towed home. Put a fresh battery, points and a gallon or two gas in it and fired it up. Ran good I thought. It has a Chevy 235 from 58- 62 as best as I can trace the casing #'s.
No brakes though. Made a few rounds in the back yard with 3 tires that would hold some air and a flat, then backed it into it's new storage shed. 18 years or so has gone by.
Time to get it going and back out on the road. Decide what I want to do from that point. First, just get it going and stopping.
Piddled with it since fathers days. Same routine as above except fresh gas from a temp jug. She woke up.
Has a miss but I'll do a complete tune up and oil change before I try and drive her.
Brakes!, got to have them. Put new shoes, springs, adjusters, wheel cylinders and cylinder lines on and decided I'd pull the master today. So glad I did. This is what fell out when I pulled the bore cap off.
This was all in the bore. The fluid and inside the reservoir truly looked good.
Ran out of cleaning fluid, so decided to finish when I pick up a rebuild kit. Lucky me, the cylinder bore looks good with no pitting so for. (the pics are when I first broke it open) So glad I didn't try and bleed these brakes yet. This crap would for sure plug a line.
Going to break the lines at the wheels and blow them out good before I proceed.
Anything else anyone know of I should look at on these brakes that I might be missing?

[mongocanfly]

Replace all the rubber brake lines...they break down with age

[1project2many]

That chunky stuff could be corrosion caused by an aluminum piston in the iron cylinder. Be sure to check the piston for corrosion or damage. Also check the wheel cylinders for the same problem.

[MARTINSR]

I am lucky enough to have a parts store in town that probably has that in stock.

Brian

[Black_Sheep]

For peace of mind I'd change out the master cylinder, wheel cylinders and hoses. With a single pot master cylinder you will lose all braking if any single hydraulic component fails. With all new parts it would be a great time to switch to DOT 5 brake fluid. It does not absorb moisture so you can prevent rust contamination in the future.

[HRD]

Thanks fellows.
Ya' bear with me. I'm trying to learn to post here as I go.

http://67-72chevytrucks.com/vboard/member.php?u=155310
Put new rubber lines from wheel cylinders to lines on truck. Didn't see any others while I was under there. Traced brake lines and didn't see any kinks or spots that looked/seemed week. Will check again to be on the safe side. Thanks

http://67-72chevytrucks.com/vboard/member.php?u=1695
I like dealing with local folks too. ASC, (Auto Supply Co) Bowdon GA. 10 miles away and he's always had what I've asked for. Big chains, NAPA, zone etc... about 25 or so. Thanks

http://67-72chevytrucks.com/vboard/member.php?u=176735
New wheel cylinders and hoses, check. Master cylinder, $100 bucks and I don't know for sure where I'm gonna go yet. I'm pretty sure I'll be doing an upgrade here and that master would be trash. Wheel cylinders and shoes might could go forward is why I went new on those. Dot 5? Really know nothing about it. This is how I learn. Had got a gallon of Dot 3 to flush and fill with. Can I use Dot 5? I'll do more research. Thanks

http://67-72chevytrucks.com/vboard/member.php?u=155310
Put new wheel cylinders on as I was doing the shoes. There is still work to do on the master and I'll check it further.


Thanks for the help guys. It's been 20 years or so since I've really messed with old cars and trucks. As I get older I tend to forget/overlook. A lot I never knew.
My current objective is to get it going, stopping and drive able. I know there will be upgrades, but first I got to have these.

[MiraclePieCo]

I love stories like this.

[_Ogre]

first thing i'd do (if you haven't already) is get the truck titled and licensed in your name
no sense putting money into a vehicle you can't tag

then... along with a new mc, i'd replace all the hard brake lines,
not much of a brake system on these trucks and the mc indicates what your lines probably look like

[mr48chev]

That is pretty normal, probably still having fluid in the reservoir kept things from being worse than they could be. I know the one on my truck would look worse right now.

[HRD]

Sorry about the delay on getting back here. Gotten eat up with dag gone chiggers.
Thanks fella's.
Decided to change routes here. The master I took off was plugged in the bottom. Very little fluid was getting into the bore. Was able to clean it up good but was going to have to mail order the rebuild kit as none of my locals had one in stock.
Decided to do this after reading on several upgrades that can be done on these trucks.
Ordered this new master set up from POL.
https://www.ebay.com/itm/1947-55-Che...75.c100623.m-1
Also putting all new frame lines on to. Then the whole braking system will be all new. All other parts I've already replaced with new. Maybe this master can go forward like if I decided to do even more upgrades here.

I had already taken care of my insurance and tag before I started anything with it. Just saw a friend put a new transmission in a Nova before he had and the cops couldn't help him recoup that when they took it with a rollback. He was lucky the PO did refund his money without having to take him to court but not for the transmission. The cops didn't charge him with receiving stolen property either. I think everyone should take care of that advice before hand on any project they start now a days.

[HRD]

As stated I decided to go ahead and change out all my hard lines as I'm installing the new master cylinder I'm going to.
After trying to figure out how to get a good double flare on the new lines for two days with not a single one worth a crap. Way over a dozen tries. Carried that piece of crap flaring tool back and found someone with a hydraulic flaring tool. 7 new lines, 14 flares and $20, 20 minutes later I'm headed back to the house. Very well worth that 20 bucks to me.
Taking my time and trying to keep everything clean as I route the new lines. Blow them out good, tape the ends before I route and get them set and hooked up. Got to the hose from the frame to the rear axel.
Should I be able to blow air through this line? I can't for some reason.
Wandering if that long metal end that would be connected at the axel is some sort of valve or something. I couldn't get an air flow by blowing for either end of it.

[dsraven]

replace the rubber lines. they get rotten and can blow under pressure. especially if you plan to keep a single system master cylinder.

[GreasyLikeaBurger]

I have actually seen the rubber lines swell over time and restrict the flow. Makes for an extremely hard pedal too.

[franken II]

In the old days we used a little hone to clean up the bores and put kits in them. Might be worth a try if yer cheap like me...

[HRD]

I'm still lost here.
This hose is new even though it might not look it due to the fact of my handling installing, removing and now reinstalling it again since I decided to replace all the hard lines. My gloves aren't the cleanest and my camera ain't the best. I'm under the truck that's been setting 15 or so years since I've had it. Setting on stands now and it ain't the cleanest under there either.
Should or shouldn't I for some reason that I'm not aware of be able to blow air through this line one way the other? Is there a valve or something built into that long end that would prevent me from being able to get an air flow through it?
I'm about to order a new line just for the fact that I think I should be able to. I just don't know how that section of the hose is suppose to work. The catalog only lists it for the 51-54 1/2 tons. It is identical to what I took off.
Thanks for the help everyone.

[mr48chev]

What is the line connected to" You should be able to blow air through a line from the master cylinder to the wheel cylinder if you have the bleeder screw open on the wheel cylinder.

Check the lines inch by inch for kinks or smashed spots. Or being twisted near a fitting.

I haven't seen it on brake lines that I remember but it is real common for guys to twist a fuel line in a knot next to a carburetor and not notice it and then wonder why it won't run. That means check next to any T fitting like on the axle or other fittings.

If you didn't have the line apart that is not flowing you might take the fittings apart and see if it had the farmer fix with a brass rivet stuck in the line to block it off to keep that wheel cylinder from leaking. I've seen it a few times on old trucks and cars we drug in and did it my self on the side or the road 25 years ago when I blew a wheel cylinder and needed to get the truck back to the shop so I could rebuild the brakes. I was braver then than I am now.

You might blow though individual pieces one at a time to see if you have a restriction before hooking everything back together.

[dsraven]

not exactly sure what you are working on for truck year, but a brake hose needs to be able to flow freely both ways, otherwise the brakes are gonna not apply or else apply and not release. there shouldn't be a check valve.
my desktop with all my pics of my 57 and 58 is down now with a hard drive issue so I have no access to my old dissassembly pics,but if memory serves me correctly, there is a metal tab on the axle that the hose goes to, it is screwed into a T fitting on the back side of the tab. that whole assy is held to the axle with one of those flat metal spring clips. the steel lines connect to that T and go to the brake wheel cylinders on each side.
like said, that hose needs to be free flowing, maybe a crimp has pinched the line and it is now plugged. that hose looks just like a front brake line.
worse case scenario, grab a line from the parts store from a newer chevy truck that has a T already built into the hose. some have the T with an extra drilled hole that the diff vent goes through and holds the fitting to the diff housing that way.
anyway, post up a year and some pics of the axle where the hose connects, some pics of the T would be good too.

[1project2many]

That hose is just a hose with two metal ends. Nothing special.

I've run into several different kinds of issues with flex lines.

Most common in this area is rust forming inside a steel support bracket and pinching the line shut. Shouldn't be a problem with your new line.

Sometimes guys will damage the inside of the hose by pinching it with pliers or vice-grips. A section of the hose tears internally and acts as a check valve.

Twice I've seen a same-but-different problem with new old stock hoses. The inside lining splits or tears during installation then acts like a check valve. Who knows when some of these old hoses were made, but they will sit and wait for a buyer for as many years as it takes.

Once I had a brand new hose that didn't have a hole drilled through the end into the banjo fitting. I guess that was a DIY hose kit.

Then there's the problems that aren't man made. Sometimes a caterpillar will crawl into a hose and die or spin a cocoon up which plugs the hose.

Mud wasps can make a helluva mess if they can get into the package. They'll plug both ends of a hose with mud then you get to try and clean out the dirt after it dries.

Pulled a seed out of a piece of fuel hose once. I have no idea how it got there.

Long story short: Carefully try to feed a mechanic's wire through the hose to look for restrictions.

[SanJosesSteve]

Since you already have it all apart, I'd consider converting to a twin chambered master cylinder. New ones are cheap and don't require much in the way of plumbing to accommodate. The peace of mind knowing you have an extra margin of safety is well worth it.

I kept my drums on all 4 corners and used an un-boosted MC. I think the bracket and MC cost me $100. Replacing all the hard lines, wheel cylinders and flex hoses took just a lazy afternoon to swap out. Well worth the effort. -Steve

[dsraven]

I am totally with steve on this one. replace the master with a dual system style for your safety and the safety of others using the same road. also, take a look at all the wheel cylinders and steel lines, a bit of crud in the line can cause a lot of headaches. dissasemble the wheel cylinders just like you did the master cylinder, look for pitting or little black spots in the bores of the cylinders, thats rust spots that will eventually cause a leak. cylinders are cheap enough to replace while it's all apart and clean. flush the steel lines out into a clean container or white rag so you can see whats hiding in there. use some brake cleaner and compressed air if available. remember brake fluid is like paint remover so if using compressed air use a rag over the exit end of the line so the stuff doesn't get atomized and cause health or paint issues.

[mr48chev]

That is what most of us would do and probably the best in the long run but vehicles have been running around for over 80 years with single piston master cylinders and the only real advantage to a dual cylinder is that half your brakes should still work if you blow a line or wheel cylinder. That can be a pretty big advantage though as being able to stop at all as apposed to not being able to stop is worth a lot.

Right now read through 1project2many's post # 18 about 3 times to let those items soak in a bit.
Especially brake hosed damaged by being pinched with a pair of vise grips and the New old stock hose thing. When I buy rubber parts for brakes I want new and fresh and never buy new old stock that has been sitting on a shelf for 40 or 50 years. A lot of that has deteriorated in the box to where it may fail with handling.

Bugs packing stuff in the end of a tube or line or fitting is a real issue at times too. For some reason leaf cutter bees are in love with the nozzle on the water spray nozzle I have and even though I used it the day before yesterday you can bet it is packed with leaves. They like any kind of hole they can stuff things in.

Hole not drilled in a fitting or a completely wrong fitting for the application that someone before you dug out of a box of fittings and used because it had the right connections and threads but the orifice inside is for a special application and is tiny. Had that happen on a fuel line years ago and it took taking it all apart to find it. Natural gas fitting with a hole about 3/32 rather than the correct fitting trying to feed 2 four barrels on a 327. That took deciding to take the whole setup apart and go through it piece by piece to find.

Right now running a length of mechanics wire or unrolling that little roll of wire feed wire you saved when you pulled it out of the gun when you changed wire and using it to run though each hose and fitting would be a good start.

Main thing is don't get frustrated and take it one step at a time and eliminate as you go.

[jweb]

The hose in your photo looks like it's missing the T. Here's what they usually look like:
https://www.speedwaymotors.com/Speed...FF,104760.html

You can also use a hose with a separate fitting like this:
https://www.summitracing.com/parts/e...iABEgJC__D_BwE

Neither of these may be correct for your truck, just an example of the different styles. Also you should be able to blow air through the lines.

[HRD]

Thanks all.
The parts store exchanged the hose with no problem.
Some systems use residual check valves within their breaking set up. I was just wandering if there might be something made into that line end that would act like a check valve. I could not get air to blow through that hose in either direction. The two for the front wheels were fine. No problem getting air to blow through them.
I'm doing a complete brake change out. All parts of the breaking system will be new.
I'm installing a dual master cylinder, hard lines, hoses, shoes, springs, shoe retainers, wheel cylinders, etc. etc.
Also had my drums checked and their good to go. A small grove in one of the rears but not bad enough to have it turned.

[dsraven]

good to hear.
one more thing to check before you finish spending cashola is the brake backing plates. they get grooves worn in them where the shoes rub and then the shoes always want to fall into those old grooves which can cause a dragging brake.
hey, its only money right........?