Hello - I've been lurking here and just joined. Last week I got a smooth running 53 two ton dump truck with no brakes. It has a 1-1/4" single output master cylinder that goes to a Bendix Hydrovac booster under the bed. I'd like to keep the drum brakes and upgrade to a dual circuit master cylinder.
I could try to keep the Bendix Hydrovac. I looked for rebuild kits but haven't found any yet. I would be a lot happier with dual circuit brakes anyway.
I looked at vacuum boosters but Brother's Truck Parts said the vacuum booster doesn't work well with the two ton. I'm looking at a Hydroboost setup now. Will a 1-1/4" Hydroboost master cylinder run my brakes?
If I run Hydroboost I need a power steering pump. There's a nice bracket from Davis Speed Equipment that mounts a pump and 12v alternator on my 235. The bracket requires a 3/8" pulley water pump and a dual 3/8" groove harmonic balancer. I can get the pump and balancer, but it looks like my balancer is pressed on and I would need to remove the engine to change it.
If I have to pull the motor I'm starting to think I would be better off swapping in a Chevy 350. Then I'd be tempted to use a NV4500 5 speed too.
I'm looking to use this truck on the ranch for hauling brush and dirt with occasional trips to the dump or gravel pit. I'd like to keep the brake upgrade as simple as possible. I'd sure appreciate some advice. If this has been covered already I'm sorry I didn't find it.
The simplest and safest "upgrade" is to rebuild everything to "as new" original condition, unless you've got a degree in automotive engineering and a research lab to test the modifications you make. If single-line brakes were actually as unreliable and dangerous as people say, there wouldn't be any old trucks left for us to tinker with. They would have all been wrecked because of failed brakes decades ago. I've seen some older Class A motorhomes with a dual line master cylinder and two small hydrovacs, one for each master cylinder chamber. No, they did not work well, and they were a nightmare to work on! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
A few years ago we talked about this at the Reunion in KC and several others there had done it. I’ll have to find my notes but I bought the parts they suggested and am getting ready to change my setup to dual master cylinder without the Hydrovac. I’ll let you know how it goes. I’ll look for the guy who gave me the info.
I think I'll try a Hydroboost 1.25" dual master cylinder and see how it works. I appreciate older engineering but there is a reason we don't use the same systems we did 68 years ago. I do have an engineering degree and I like to test things out. I'll post the results.
I still wonder if I should try to put a power steering pump on the 235 or swap in a 350 V8. Do I really need to remove the engine to change the harmonic balancer? I guess I can ask Davis Speed Equipment about that since they make the bracket.
Do you have enough room to use a crowfoot puller on the balancer? it's a press fit- - -no center bolt. Just pulling the radiator will give you more working room. 2-sheave pulleys for 235's are as scarce as honest politicians, and almost as expensive as Rolexes.
Good grief- - - -another train driver! I'm really wasting time giving advice from only 60+ years of actually making a living fixing these old rigs, and 30+ years of teaching the trade. Good luck! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
It looks like the balancer can come off with a puller if I remove the grille and radiator. Don't have to pull the engine. There are a few 2 groove balancers on ebay right now for about $100. I have one coming, hope it's right. You can get a new one for $250 at Damperdudes. Also ordered a P/S pump, bracket, and alternator. I like this stovebolt engine. I'll try to keep it in the truck.
I have a 1984 Ford B700 bus with a hydraulic/electric brakes and 4 wheel drums. I think the bus master cylinder/booster would work on the 53. I'm looking for a salvage part now. The Ford 370 bus engine has a GM power steering pump on the right front of the engine that only runs the brakes. There's a separate pump on the left front for the power steering assist.
The B700 master cylinder is 1.75" which is a lot bigger than the Chevy 1.25". If the pedal feel is wrong all I should have to do is change the master cylinder.
The B700 front and rear drums are dual slave. The Chevy is dual rear and single front. If the brake balance is off I guess I can try a proportioning valve.
Use a 2-sheave damper for a 250 6 cylinder. They're on Ebay brand new for under $50.00. It's necessary to shorten the snout by 1/4" and machine the OD back the same distance to make the belt grooves line up properly- - - - -or throw a big chunk of money away by dealing with damper Dude.
Hydraulic/electric was NOT one of Ford's better ideas. The idea didn't last long in production, and 35 years later, it hasn't improved any. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
That 250 damper looks like a better design but the grooves are further apart than the 54-62 balancer that the bracket maker (Davis Speed) said to use.
I had an 03 GMC/Isuzu box truck that also had hydraulic/electric. I had to rebuild the brakes and the parts cost a fortune. I think one rear drum was over $400. I think they use hydraulic/electric so you don't need a CDL. Air brake parts are cheaper but I don't have a CDL.
The 250 damper is a poor design, probably dictated by the bean counters, since the bonded rubber between the hub and the outer rim carries the driving load for the belts, but nobody but a nitpicker with something to sell you would be concerned about a tiny fraction of an inch of belt spacing. In the real world, it's a non-issue. There are hundreds of them in use by people who don't want to pay the outrageous prices the rebuilders want for the original ones. There is also a way to fabricate a balancer using a 6" diameter V8 damper and a 2-sheave pulley for a big block V8. I've made several of them and stovebolters are running them without issue on engines with power steering, air conditioning, and other setups that require two or more belts. Coilover's shop routinely installs serpentine belts on stovebolt sixes, using off the shelf parts and a little common sense. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I noticed the 250 damper has the pulley on the wrong side of the rubber. And I'm a nitpicker about belt alignment.
I also remembered wrong about the 03 Isuzu, it had some kind of air brakes.
I bought a Hydromax booster and a 1.75 master cylinder on ebay. Total cost $250. The fun starts with the fittings and lines. The hydromax with electric backup is from a 2002 Chevy C6500 so maybe it's not just an old Ford thing.
I haven't fallen in love with the old stovebolt enough to do a serpentine setup, but maybe with time!
You'd better spend some time in the gym doing squats- - - - -you'll need all the help you can get with both feet on the brake pedal with that huge master cylinder bore. You'll have a VERY short pedal stroke, though! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I would venture to say that most of these guys that think they have to improve on hydrovac brakes have never driven a truck with a properly functioning hydrovac system. I grew up riding and later driving two ton bobtails delivering gasoline in the Texas Hill Country. From when I first started riding along in the late 1940'S until I bought a semi with air brakes in 1964 all we had was hydrovacs. And they would stop a 2000 gallon load of gasoline just fine. And we went faster than most people realize. We weren't afraid to run our gas GMCs up to 70 mph and we had no trouble stopping them. I wonder were this guy went to buy brake parts. I had an Isuzu NPR for a while. I bought rear drums for less than $100 each 10 years ago. I notice they are up to $130 now.
Dad had a 49 Olds 98 in the early 1950's that was the fastest one in the middle Tennessee area. He used it as a test bed for several hotrodding projects on the then-new overhead valve Olds and Cadillac V8's, some which ended up being incorporated into a different style of "tanker" for some guys from the east Tennessee mountains. He won a hydrovac as a door prize at a garage owners' banquet sponsored by a local parts warehouse and fitted it to the Olds. Just one little problem- - - -it was sized for a 3/4 ton truck! It took a VERY gentle touch on the brake pedal to keep from locking up the wheels at every stop.
"New and different" simply for the sake of change sometimes results in butchered-up rolling deathtraps, even when the intentions are good. Ambulance chasing lawyers love to put those guys in their crosshairs! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I just wanted to take a moment and add how well the original brakes perform. I put my 54 4100 back to original and it has the best brakes of any vehicle in my fleet. That includes my modern vehicles. Even with 2 tons in it, it still outperforms all my other vehicles in braking.
Yes I wish it had a dual master, but I have had dual masters completely fail (1981 F100) - since I experienced that I put less credence on having a dual master. Instead I periodically go over the entire braking system - very easy to do since the truck is easy to get under. I check master cylinder level before every outing.
I have only once needed the safety of a dual master in 40+ years and is was because no one kept an eye on the rubber brake lines (1967 camaro back in 1978).
Anyone who has done a serious study of the internal plumbing of a dual outlet master cylinder and gained an understanding of how the thing actually works probably won't be as anxious to bet his/her life on that incredibly complicaled piece of Rube Goldberg engineering working as designed in an emergency. Complex designs add a degree of potential error that I find to be totally unacceptable. People who are willing to draw to an inside straight in a high-stakes poker game might have a different level of confidence in the things. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I'm glad everyone's brakes are so good. My truck doesn't have brakes that work right now. I'm looking forward to getting them working. Hydrovac parts are hard to find. Single circuit master cylinders allow complete brake failure with a single leak. Dual circuit master cylinders can still fail but they've been working out ok for the last 60 years. A 1.75 master cylinder would take a lot of pedal pressure if it didn't have 2,000 psi of hydraulic assist.
Crenwedge is sure right about the 2003 brake drums. The GMC/Isuzu was a WT5500 cabover with a Duramax 7800 six. I was away from home when the brakes went out so I took it to a shop. I just checked rear drum prices and it looks like I was ripped off big time.
I rebuilt the whole brake system on my 1962 c60. All new wheel cylinders, shoes, hoses, lines and master cylinder. The hydrovac was rebuilt by one of the only rebuilders in my area and it soon failed. The hydrovac may have been good back in its day when they were new but good cores, rebuild kits and rebuilders are hard to find, it was the obvious weak link in my new system.
I ended up going the hydroboost conversation route and wish I didn’t waste time and money fussing with the hydrovac.
I’m planning on doing a full post on it but I want to get more seat time before reporting back on it. After a few months I finally found a company willing to insure the truck and got to drive it for the first time yesterday. The brakes work great so far with plenty of stopping power and a great pedal feel.
My truck has a 327ci. I made up custom brackets and mounted a Saginaw power steering pump. Hydroboost and master is from a 2005 Suburban 2500. Clutch master is from a mid 60’s International truck. I had to make a firewall plate to mount them. I extended the clutch torsion rod 4.5” because the clutch master is now mounted that much wider away. The new hydroboost rod was welded to the old adjustable master rod. I used a high pressure line from the suburban which I cut and spliced (using proper fittings) to get the length and shape needed. Return lines are low pressure since there is no restriction from a steering gear.
Not sure when I will get a full thread on it posted so if you have any questions or want part numbers or specs let me know.
So did you use a hydraulic clutch linkage? I see dual belts on the alternator. Nice. That 327 has a lot of room in there.
I got a used ebay balancer for the six today but it was wrong. It was a single groove. Looked like a 2 groove in the picture. Sent it back. I'm going to try to modify one from a 250 like Hotrod Lincoln suggested. I can use small spacers on the brackets if I need to align the pulleys. I want to get the truck going as simply as I can for now. I think a v8 may be in the future.
I can't decide if the brake master should go under the floor with the integral reservoir, under with a remote, or on the firewall. I like the way you did it. Firewall is sure accessible for bleeding and checking fluid levels.
I need to get after the wheel cylinders and look at the shoes. I haven't even tried to get them apart yet. The parking brake shoes need to be relined and the linkage gone through too.
The clutch was originally hydraulically actuated, I did replace the slave and lines as well on that.
I wasn’t able to find a two groove alternator pulley that was the right size so I machined the new one down and bored out the old one from the generator and welded them together. [img]https://imgur.com/a/aMHW7R0[/img]
There is the option to mount the hydroboost remotely and still use the original master. As slave cylinder would need to be mounted on the hydroboost to actuate it from the master, similar to how the hydrovac works. But for me that was going to be a lot of extra work. After fussing so much with this system I just wanted something that was going to work and be as reliable as possible.
Several years ago, I was considering switching over to a dual reservoir system on my GMC 2-1/2 ton. I too, can appreciate the advantage of not having a single leak take out the entire system. I have experienced partial system failure on dual reservoir equipped cars twice in my lifetime, and while whatever is left tends to be marginal at best, its still a better than nothing.
After running some of the basic calculations, the main part I kept coming up short on was total volume. With tandem rear axles, and a total of 6 wheel cylinders, I couldn't find a solution that would readily package, and still accommodate my system. I considered the Hydroboost system, but was not crazy about trying to add the pump and related lines.
So, I got a rebuilt Hydrovac from NAPA, replaced all lines and hoses, and SS sleeved & rebuilt all the cylinders. Every time I take the truck out, one of the first things I do is press the brake pedal as hard as I can. I would much rather have something fail in the garage than on the highway.
If anyone is planning on going down the road of re-engineering their brake system, here are a couple of resources that might be of interest:
The first is an SAE presentation by a Chrysler engineer. It is a little old, as it does not include much on modern systems with ABS (which I doubt we really care about anyway), but it has a lot of good information on the fundamentals of brake system engineering.
I also found this book to be pretty interesting. I borrowed an older version from one of the chassis engineers I used to work with. I don't remember everything in there, but it did cover stuff like adding line flex into the total volume calculations, thermal considerations, valving, etc. etc.
Volume was also a concern of mine. Here is the math I used to determine the surface area of all of my wheel cylinder pistons:
1.5” dia rear cylinders = 1.76 surface area
1.76 x 8 = 14.08
1.125 dia front cylinders = .99 sq” .99 x 4 = 3.96
Total 18.0 square inches of piston surface.
Now I don’t know how much more travel due to clearances there are in disc vs drum brakes but the donor vehicle has 4 wheel disk with large 3” pistons for a total of 27” square. So I’m under by roughly 10” square in volume.
I still had my crossed the first time I applied the brakes after getting it all together. With the system bled and shoes adjusted I have a nice high and firm pedal that doesn’t take much pedal effort or travel to get stopped, the master has plenty of volume and hyrdroboost provides plenty of pressure.
I did not upgrade to disc front. I have a 1962 with torsion bar suspension, not sure it has ever been done. I believe I read the brake bias is such that the rear does 70% of the braking anyways.
