Older Medium Truck Hydraulic Brakes

[Alan]

I don't know who the best ones to ask are, but I'm thinking Fred, John and Jerre but anybody who has anything to add please chime in.

My son just called, he was using my '71, 5500 to do repairs on his driveway when he lost a brake line. He had his daughter with him when it popped and they took a pretty exciting, if short, run down the driveway as a result.

This truck has only a single system, so lose one, lose them all. There has to be a better way. There are no truck yards around here so I can't do any legwork locally myself but I want to research the viability of putting a split system on this one.

The line that went was replaced in 1999 when I restored the truck. Eight years, not real impressive corrosion performance from replacement tubing. The only original line on the truck blew on me two years ago, loaded and in traffic, which was fairly thrilling as well. :)

I assume that newer trucks adopted a split system but I've never looked at one. Did they use a remote booster like this dinosaur has or did they go to a firewall mounted booster/master cylinder like the light trucks? What years/models could I look at for parts to make the conversion?

Hopefully this is a viable option. The other thing going through my mind right now is that if one of my replacement lines was going bad the others can't be all that far away. Only option other than the split system, which I would like to do anyhow, is to go with stainless or Cunifer (http://www.fedhillusa.com/) lines for the time being.

[jakegypsum]

Alan,

The older trucks that we had years ago all had the split system with the remote mount booster. They were set up very similar to pick up truck configurations of the same year.

My '72 F-700 had the booster mounted under the cab on the drivers side with the vacuum exhaust vent set right under the seat inside. I forget how it was plumbed using both legs of the system though.

Perhaps maybe only the rear wheels were "boosted"? I'm not sure.

My early '70s Internationals (loadstars, Cargostars) all had single bowl master cylinders with twin lines out of the bottom to their respective axels. I believe that they were boosted remotely also but not sure where the booster was mounted on the truck.

I do remember that back in the older days (30+ years) most of the primary braking on a med duty truck was done with the rear brakes where as in the past 20+ years more attention to stopping power was put on the front axel as well.

Have you tried some of the online truck shops? Perhaps you could go with components for a younger (newer) truck and adapt them to what your have? Or, possibly look into something aftermarket?

Hope this is of some help.

Jake

[Alan]

Jake, what I'm hoping to do is find out when the split systems went in use and then see what I can retrofit to this older chassis.

In all truth it may not make sense to put a bunch of time/effort/money into a truck that is approaching 40 years old. On the mitigating side is that this truck is in amazingly good shape, under 100K on the odometer with less than that on a Goodwrench engine. It carries 5 tons with no effort at all, starts 100% reliably, regardless of weather and I just flat enjoy it. I grew up driving trucks of the same vintage so I'm right at home with a 4 X 2 gearing setup and a gas V-8.

The only part I don't like is the single braking system. I've had three brake failures due to rusted line over the years, not all on this truck. My luck has been good and none of them have resulted in any damage or injury. My last rideout was in this truck, and now this latest with my son driving. This one could have been a hell of a lot worse. He was working on his own driveway and had his 4 yr old daughter with him. He grew up driving modern trucks with air brakes and never thought of the handbrake(which works, btw) lever sprouting out of the floor. The truck stayed upright around a fairly hard turn down a connecting driveway and rolled out onto the neighbors lawn.

Every line, except the one across the frame to the right front wheel, was replaced in 1999 when I got the truck. That one line wasleft in as it showed no rust anywhere and looked like a real bear to change out. That was the one that split on me two years ago, it had rusted where it laid against the frame crossmember. 1/4" from where it rusted through it was still gray and in perfect condition, there was just oen small spot where dirt and moisture laid against it to cause corrosion.

At the least I'll go to corrosion proof lines but the ideal would be to upgrade to safer system. Right now I don't even have a starting place to look for parts, agewise. The online yards I've searched only work if you have a year and model number. If I can get some hard data about what years to start with I will run it down from there.

I'm thinking the new 45/5500 GMs use a split master on the firewall. But I have no idea if it would be possible to retrofit that to an older, all drum system. I've never seen a split setup with a remote booster but that seems like it might be the transition setup and could be adapted. I've done my share of barnyard engineering to make stuff work in odd applications but I hesitate to do that on a brake system.

Realistically I'm probably better off to go with stainless or cunifer lines start to finish. I got eight years out of the replacement tubing I used last time, it should be realistic to expect 10+ out of the corrosion resistant stuff. In ten years I'll be 68 and either I, or the truck will probably be long gone by then.

[jakegypsum]

Alan,

I started to rattle my head a little and think of all the different trucks that we have had over the years.

One that comes to mind is a 6500 Sierra that we purchased back in 77 or 78. It was a gasser (350 v8) with a five speed, 16' box body, and the GVW was rated at 26,000 lbs.

This truck did have:
1) Juice brakes w/ split system.
2) Firewall mounted booster.
3) Four wheel drum brakes. (Larger drums on rear w/ dual wheels)

Hopefully this info can help.

I know what you mean by considering the age of the vehicle and if it is worth it to keep or let go.

I have several class 8 trucks that we use for back-up replacement use mostly. Trucks that are well over twenty years of age.
No plans to sell or replace them at this point either.

Jake

[Pickering Snow]

Alan

Ill post in the morning on this long day. couple options for ya.

[Jerre Heyer]

Fred, Thanks for the go to bed call this am. Know you had a long day too.

Alan, We usually scab them off of C60 and C70's and modifty the mount if necessary.

Jerre

P.S. this is the times we want / need brakes. Usually just steer for a tree.

[Chuck Smith]

Usually just steer for a tree.

Aim for a Pine if you can, trust me.....

~Chuck

[Pickering Snow]

Ok were to start, first on just about anything newer 98 and up which would be a easy find in a salvage yard they run single tank masters , Ford, GM and Dodge, on anything over a 3500 they use a Hydro boost off the firewall has well its not just a diesel thing anymore.

So with that said even the new trucks have went back to the old way except they hold a hell of alot more fluid than your truck or even my 60's set up.

The options Jerre and Jake listed would be my choice for conversion and those time Eras only thing you need to understand is using a vac booster and split master like from the late 70s to mid 80's is there running disc front brakes so in theroy you will need to hook the portioning valve up basicly backwords as you dont want a 60/40 combo on 4 wheel drum set up, 60 to the rear would be ok and 40 to the front so it would be reverse when converting a disc/drum master over to your truck.

Now if you want my honest opionion since trucks have went back to non divided masters anyway the best route to me is reline the truck using SS, Cunifer, or my choice Epoxy coated lines from Auto value, Iam not that impressed with Cunifer and when we do resto work i always used SS lines but honestly the new Epoxy coated " Looks like OD Green line" works has well and cost far less than the other two and holds up the same if not better.

If i was doing this for me again i would reline the orginal set up and get the Ebrake system working right most older trucks used the same handle style with release handle giving you a cut brake if the crap hits the fan on the hydro end again.

I have built many sand rails and installed CNC pedal assemblys using hydro brake and hydro clutch systems neither fuild cup held more than 8 ozs of fliud meaning if you had a line failure on a dune buggy street driven you were screwed on the first pump , i always invested in the VW e brake cables and handle release for them giving them a Cut brake and a way to stop the thing if i lost hydos.

Its very doable Alan using the years i and others listed but i wont bs ya your gonna have to do some fab work which i know you can do and also have to do alot of plumbing and its gonna take some man hours to do.

My 60 is the same has yours 4 wheel drum single squirt system and i dont worry i bought the parts for the Ebrake with release handle and i have tested that truck a few times stoping off just Ebrakes rear drums no problem.

On Ebrakes iam anal about them working right older wreckers used to use a Micro brake which held hydro line pressure when set my dads wrecker almost made me apart of the block wall at the shop when i was 17 when a line blew on it the truck had working ebrakes but i thought the line lock was cool back then.

[Alan]

Fred, who makes flaring tool worth owning? My current one is a generic, fairly low buck, and leves a bit to be desired. Ray and I got a line made for the old girl Saturday so I can get it home but it will be getting all new lines before it travels much further. I hate using premade lines, there's always too much and it ends up hanging out in the breeze. I might go with premades so I could avoid flaring at least one end but that still merans I have to flare some and my current kit does great at making the flares off center and scraping the epoxy coating off the pipe.

Is it common that the pin on the double flare adapter is a sloppy fit inside the tube? The one for 5/16 line will very nearly fit in 1/4", it's rare that I get a nice uniform flare. I'm fussy about stuff like that, and more so because it's the braking system.

The hand brake works fine. This is the type that comes up through the floor and goes over center to apply, then you push it forward and it springs all the way off. I think if Ray had remembered it was there it would have stopped him fine, truck was empty and moving at walking speed when the line blew. He was right at the top of a pretty fair hill and gravity did the rest.

[derekbroerse]

Alan, dad's had a Bluepoint double flare kit in the garage for as long as I can remember... I think they're part of Snap On now, aren't they? Anyways, it obviously hasn't been used commercially but has always done the trick for us on any vehicle, that is, until we started needing bubble flares... but thats another story.

Good luck on your brake upgrade.

[bterry]

Good advise so far.

Keep in mind that manual brake master cylinders (either single or dual) will use a smaller bore size than a boosted cylinder. IE: manual will have say a 3/4" bore while the power brake master cylinder will have up to a 1 1/4" bore. Now that said - you can switch them all around, but if you use the wrong ones you might not get the pressures you want for that big truck. Or in some cases you may not get the amount of fluid you need to adequately move the wheel cylinders (although I don't think thats the case here, because of it being a manual brake/small bore setup). Wheel cylinders use far less fluid than calipers.

Also, some master cylinders have two bore sizes - especially those with disk/drum setups. Thats why the front brake resevoir is in the rear - big bore front/small for the drums out back. If you ever take a dual master cylinder apart - you'll see why the big one has to go in the rear.

Sorry to confuse your issue with no real part number help like you asked for.

[Alan]

Sorry to confuse your issue with no real part number help like you asked for.

No problem, it's all good information, thanks.

[Pickering Snow]

Sorry Alan

I didnt see you repley back on flaring tool i have a snappy about the few things they seem to make decent ,,, i use there Tap and dies has well or Hansen

Trying to remember but i think Lisle makes a flaring tool which i like there stuff and there aval at most decent part stores.

Has for running the lines see how close you can get with math on what you need you might be suprised the combos would be close they come in 6 , 8, 12,20, 30, 40,51, and 60 inch lengths at least it might cut down on how many flares you have to do.

[Fastjohnny]

My craftsman doulbe flair set has been ok for me, don't use it often, but its performance has been satisfactory when needed.

[Alan]

Has anybody ever used this one by K-D?

[paulsoccodato]

alan,
ive used a lot of different types of flaring tools. the biggest problem with some of them is the lack of clamping pressure by the tool while you tighten the die down. usually pushing the tubing out and ruining the flare. try putting a vise grip on the tool directly where the tubing is. usually works.