The Stovebolt Site Forums The Parking Lot Big Bolts Upgrading Brake Booster

So I have a silly question: is it possible to put a 1980s car brake booster on my 5500? The current brake booster is just not giving out enough brake assist and I have a spare firebird brake booster laying around. Just curious on y'alls thoughts. Dont have money to upgrade to a hydrovac system (or what ever that newer system everyone says to upgrade to is).

Hy GMCDumpTruck72, welcome, the simple answer to your question is no. Heavy truck braking systems were in a state of flux from the mid 60s to the late 70s. Single systems with a remote booster, single systems with the booster mounted integral to the master cylinder. Dual braking systems with two remote boosters, dual systems with the booster integral to the master cylinder. Newer trucks got dual system brakes with a hydraulic booster mounted integral with the master cylinder. Your braking system was designed to stop your truck safely fully loaded. If you feel your braking power is insufficient, I suggest a thorough inspection of your system is needed. Your brakes could be out of adjustment, your wheel cylinders may be seized, your flex lines may be restricting from deterioration on the inside, your hard lines may be plugged with rust. If you intend to drive this truck on the road with us, I strongly suggest a complete overhaul of your trucks braking system, for your sake and ours. Come back if you have more questions.

Agree with 3B. However, hydro boost systems are very simple, pump off GM and others, brake master assembly same place, need deep 15mm socket to get master off firewall. Several factory lines available or make up new lines. Need to get master input shaft properly adjusted. No need to fool with lines or slaves.

Ed

All brake lines, brake cylinders, master cylinder, and brake shoes are brand new. All thats left is the brake booster. we tried taking it apart and restoring it but we still have a vacuum and slight fluid leak from the booster itself. We just want to figure out how to get assisted brakes because we can stop the truck, the brakes hold really well, but its too stiff for normal driving. we do not like the hydrovac system of the 70s and are wanting to try something modern.

I rebuilt the entire original system on my '57 2 ton. Recently rebuilt the Hydrovac and put it back into the system with great results, prior to the hydrovac rebuild I was very confident with the brakes even with no booster but now it responds like the truck was designed. I have no regrets to using the original design, it served millions of trucks for untold miles and still does a great job. Just my opinion.

Hy GMCDumpTruck72, you cannot tell how efficient a braking system is when it has vacuum and hydraulic leaks! First you have a leak free system. If you did do all those repairs/replacements, did you bleed the system as per the instructions in the maintenance manual? Bleeding a braking system with a Hydravac is different than one without one. Get your system leak free and bled as per the manual and then see how you like it.

GMCDumpTruck72 Your comment about "to stiff for normal driving" means you don't have any assist,that is how they "feel" when booster is not helping. Does it ever make any noise?? To check it get in engine off --pump brake pedal to use up all vacuum,hold pressure on your pedal start engine,pedal should advance a little. Boost is applied.

GMC DUMP Wouldn't try to use the car booster,is best to put it back the way it came new,GM had it right. You know I oncee had a 65 big truck dumped in my lap that had intermittent brakes,I couldn't fix it!! Shortly left that company,a hot shot mechanic came in changed that real stiff vacuum hose from the intake to the booster--fixed it--would stop on a dime give back a nickel in change. I have never forgotten that--that hot shot became a hero,is now horizontal in the ground!!

we lose vacuum as soon as the engine turns off. We took back off the hyrdovac and noticed that the rear seal was leaking once more. we decided just to buy a new one in the end. thanks for all the advice from everyone though!

UPDATE: For everyone saying to replace the old parts, FIND THEM PLEASE. Currently there are no places in the USA with ether a rebuilt hydrovac system OR the parts to replace them. All the websites shared in the past are down, Napa cant find one in the entire USA. There is nothing we can do

Geoffrey Rosenberg at Alretta Truck Parts in Massachusetts (508) 788-9409 has tons of brake part knowledge. I bought all my brake parts from him including my remanufactured hydrovac from him a few years ago.

Did you try either of these?

https://harmonclassicbrakes.com/

https://www.brakematerialsandparts.com/booster-rebuilding - these guys relined all my old shoes

GMCDumptruck72 My 51 6400 with I think the booster that came new with it will slide the tires. Only improvement there would be ABS,it helped it to service it with bendix vacuum cylinder oil which is hydraulic jack oil from your local FLAPS.

Hy GMCDumpTruck72, do you have any numbers or tags on your Hydrovac? As I said previously braking systems were in a state of flux and there are many different options available. I don't believe you ever told us if your truck was a single axle or a tandem. There is a company in Portland Oregon, Brake Systems INC., they can rebuild your booster if they don't have one on the shelf.

GMCDumpTruck72 I can't think that in the land of big trucks,that no one can fix that booster. When I drive thru there it is gobs of oil field trucks 6x6 on down!!

GMCDumpTruck 72 You are in the heart of big truck country,can't think there isn't a booster repairer in Oklahoma ???

https://www.stovebolt.com/ubbthread...last-post-a-sad-goodbye.html#Post1458688


They fixed the booster and are sending the truck down the road.

You need to call these guys. They made my 1960 C60 booster work like new. And it had sat for 27 years in a thicket. They are in San Jose Ca. Martin rebuilt mine in a day.
Power Brake Exchange, 2870 Alello Drive, San Jose Ca. 408-292-1305. The real old ones like this one are pricey to build. I paid around $300. But that truck now stops on a dime. Shops from all over the US will accept your unit for rebuild, charge you a fee and send them out to these guys. I'm lucky. They are about 15 miles from my home.