my hydrovac eliminator project

[Mike Van]

The hydrovac on my 1974 Chevy C60 went bad a few years ago, not an easy thing to find. Lots of places listed them, but "out of stock" was the always the answer. I bought a new modern unit from a seller on ebay, about 180.00 which i didn't think too bad. The old setup had just one line from the master, lose any brake line, lose everything. That happened more than once, I was always lucky, manual transmission, parking brake that works, and driving smart. So, after some cold days in January [out on the ground] got this new setup in & working.

Once installed, I had some major brake line work to do, replaced pretty much all of them, had to split the old system at a T so half the new unit feeds the front shoes, half feeds the rears. Have to adjust the rear shoes now, as the fronts are grabbing first. I still have some work to d under it [once it warms up] Getting rid of the old vacuum lines, etc. Anyway, this job was long over due, it's a safer truck now.

 

[Tom in Mo.]

Brakes are very important. Well done.

 

[c60 boy]

The hydrovac on my 1974 Chevy C60 went bad a few years ago, not an easy thing to find. Lots of places listed them, but "out of stock" was the always the answer. I bought a new modern unit from a seller on ebay, about 180.00 which i didn't think too bad. The old setup had just one line from the master, lose any brake line, lose everything. That happened more than once, I was always lucky, manual transmission, parking brake that works, and driving smart. So, after some cold days in January [out on the ground] got this new setup in & working. View attachment 106069 Once installed, I had some major brake line work to do, replaced pretty much all of them, had to split the old system at a T so half the new unit feeds the front shoes, half feeds the rears. Have to adjust the rear shoes now, as the fronts are grabbing first. I still have some work to d under it [once it warms up] Getting rid of the old vacuum lines, etc. Anyway, this job was long over due, it's a safer truck now.

Hi Mike. I have a 74 c60, and want to put a dual line master/booster on it. Your picture looks like what I need. There are a load of people on ebay selling set ups like yours. Can you point me towards the vendor who sold you the one on your truck? Thanks in advance for the help.

 

[Mike Van]

If this link works, you're all set - https://www.ebay.com/itm/325882157217 if not, let me know -

 

[c60 boy]

Thanks for such a speedy reply. I looked at the pics and read the specs. My question is that this cylinder is 1 1/8" bore and the old original cylinder was 1.5". Have you had any issues on stopping power when your truck is loaded? Also were there issues with connecting the push rod from the booster to the brake pedal? Thanks.

 

[Mike Van]

If your shoes are adjusted right, I don't think the bore matters. It'll only take a small amount of fluid to move them against the drums. The push rod needed some work, as the brake pedal on the truck is too thick for the pushrod. supplied. This was a chore, but I finally filed enough off the insides of the clevis to make it fit. You'd think there's a lot of room up under the dash, but it's pretty tight. So far, i'm happy with it.

 

[c60 boy]

Thanks for all your help.

 

[ChevyC60Dude]

The hydrovac on my 1974 Chevy C60 went bad a few years ago, not an easy thing to find. Lots of places listed them, but "out of stock" was the always the answer. I bought a new modern unit from a seller on ebay, about 180.00 which i didn't think too bad. The old setup had just one line from the master, lose any brake line, lose everything. That happened more than once, I was always lucky, manual transmission, parking brake that works, and driving smart. So, after some cold days in January [out on the ground] got this new setup in & working. View attachment 106069 Once installed, I had some major brake line work to do, replaced pretty much all of them, had to split the old system at a T so half the new unit feeds the front shoes, half feeds the rears. Have to adjust the rear shoes now, as the fronts are grabbing first. I still have some work to d under it [once it warms up] Getting rid of the old vacuum lines, etc. Anyway, this job was long over due, it's a safer truck now.

I just bought my C60 hydrovac from this company. I'm waiting for it to arrive so I can get my truck back on the road. I'm hoping this will be a good hydrovac unit.

2508827 Bendix NEW Hydrovac 2512065 Chevy GM Trucks

2508827 Chevy C60 Hydrovac Booster

acemotorparts.com

 

[The Old Codger]

As mentioned if the brake shoes are kept in close adjustment, the bore size won't matter that much. It actually does matter but only in a panic stop as the larger bore will impart more hydraulic force through the system with slightly increased pedal effort. When I convert there is a peak gauge installed into the front line at the master. Between 900, and 1200 psi better lock those brakes up with acceptable pedal effort on dry pavement to be effective in practice.

 

[wore out]

"I just bought my C60 hydrovac from this company."

IMHO, it makes a LOT more sense to do the conversion and convert to a "split braking system" and dash-mounted booster (if possible on the truck in question) rather that pay that sort of money for a reproduction hydrovac with the deadly single braking system.

 

[The Old Codger]

"I just bought my C60 hydrovac from this company."

IMHO, it makes a LOT more sense to do the conversion and convert to a "split braking system" and dash-mounted booster (if possible on the truck in question) rather that pay that sort of money for a reproduction hydrovac with the deadly single braking system.

I would agree but use an adjustable proportioning valve in the system as they're never balanced if one is not incorporated.

 

[Sprint 6]

I would agree but use an adjustable proportioning valve in the system as they're never balanced if one is not incorporated.

Adjustable proportioning valve aren't DOT approved.

 

[The Old Codger]

They are not approved; that is correct but in reality but they greatly enhance braking safety. That is legal jargon for manufacturer liability release My first rollback car carrier trucks were hydraulic brakes and each had adjustable brake proportioning valves incorporated into the rear service brakes; controlled from within the cab. Trucks, and braking effort are a different animal with two on the deck, and one on the stinger, from deadheading empty.

It is a great asset when one lives in reality rather than citing a staff writer's work in some sort of text. Went through many scales, and many inspections with an adjustable proportioning valve incorporated without a single problem from any enforcement. Hydraulic braked trucks all had "Mico Lock" brake holding valves also that kept them stationary while winching.

Your mileage may vary and I'm only relaying what I believe works through positive experience. Had I had problems, it would also be revealed as I operate quite transparent.

 

[Mike Van]

In the early 70's our line trucks all had Mico brakes - Flip the lever up, step on the pedal and go to work. I've heard they could bleed off after awhile, but never saw it happen.

 

[The Old Codger]

In the early 70's our line trucks all had Mico brakes - Flip the lever up, step on the pedal and go to work. I've heard they could bleed off after awhile, but never saw it happen.

They can and will bleed off as they age and through use. Takes a long time to bleed down however. Damned nice system to have and worked flawlessly in the applications I used them in.

 

[Sprint 6]

I fully understand the difference between the rules and reality. But I also know that getting stopped and inspected around here with non-DOT approved equipment is an automatic red tag out-of-service and a very expensive tow bill. Then proper repairs an another inspection to get the red tag removed. Everything is legal until you get caught.

Not that the OP's setup would pass, either. A pickup booster isn't going to supply enough boost to stop a truck that size because that 350 in a C60 won't produce enough vacuum volume to deal with depletion during braking. There is a reason the original Hydrovac was huge, vacuum storage. A 350 in a C60 has to be flat to the floor to run 60mph on flat road empty, I've driven several. Never understood why they put that weezer engine in such heavy trucks. Only thing worse is an International 345.

 

[The Old Codger]

I'm only speaking with my personal experiences on my own trucks and never had any problems. Can't, nor will attempt to state what worked for me would for anybody else. Don't really think I'm gifted, nor lucky, but I did run what I thought was a very clean operation including shrink wrapped loads and diapers to preclude loss, and/or leaks. May have helped having all logs in order when needed, and running the same routes routinely.

Agree on the 350ci engines in the medium duty chassis. Good engine in the application if modified for more power. One of my trucks was a C60 w/19' steel rollback and wheel lift installed. It too was a "pooch", but dead reliable. That chassis was replaced with an IH 1754 chassis having the 9.0ltr diesel and while most found the engine troublesome, mine excelled. I'd get 17mpg with that truck deadheading for another load on flatland. It too was underpowered, but very reliable for me. Bought it used as a cabinet delivery van, removed the box, shortened the frame and rolled the axle forward several inches, then transferred the bed over. Was able to use the same PTO with a different input gear so overall the conversion was very easy. Forklift and shop gantry made it much easier than blocking etc....

 

[Don B.]

I have a place not too far away that can rebuild those brake boosters. Bedford park IL. The name is Midwest (something). They've done a couple for me. Most recent was the one nobody could get for my son's 72 fury

 

[The Old Codger]

Rebuilders Enterprises in Bollingbrook does also. Good work but a bit spendy IMO.

 

[Don B.]

Bolingbrook IL? Might have to check them out