The Stovebolt Site Forums The Parking Lot Big Bolts 1972 c50 brake issues....

Hello, i just starting having some brake issues with my rig the other day. thankfully it was noticed while going pretty slow and on our farm. Basically whats happening when i hit brakes is it starts to slow down then pressure drops out and when pressure drops my booster vent is making noise and my engine idle changes. But this only happens intermittently. I just bled brake system this morning and took for drive definatly working better but still loosing pressure after about 5 braking events in row(intermittently). And if i pump brakes when stopping after the 2nd or 3rd pump i can make this prssure drop happen it seems...... i do not have any brake fluid leaks and have res topped off after bleeding. Any input would be great...

thanks mike

And btw when this pressure drops out my pedal becomes very stiff cuz i obviously pushed harder on pedal when i wasnt stopping and it still didnt stop it, felt like i was about to push pedal thru the floor Haha. Not sure if this extra bit helps but figured id lay it out there

Hy DIY.MechanicMike, to me it sounds like you have a brake booster problem. When the booster doesn't function it actually requires more pedal pressure to be applied by the truck operator. Try doing the following test, with the trucks engine not running pump the brake pedal several times, after that put your foot on the brake pedal and apply pressure now start the engine, if the booster is functioning correctly the brake pedal should go closer to the floor when the engine starts. Normally the booster vent doesn't make noise as all it is doing is allowing air under atmospheric to enter one side (apply side) of the diaphragm inside the booster. Good luck.

2x Master Gabster.. Id bet it is the booster also

Yeah, what 3B said^. And if the idle changes with the brake application, the booster is likely leaking vacuum messing with the idle mixture, (adding extra air, leaning the mix).

Ok im gonna go try that right now. And what if the pedal doesnt go closer to floor??? What needs to be fixed??
Thanks

Hy DIY.MechanicMike, If the brake pedal doesn't go closer to the floor when the engine starts then the booster needs to be overhauled/replaced. Please let us know how the test turns out.

It failed the test haha. So whats a rebuild kit cost? And is this a simple overhaul or do you need special tools and such? And are new ones available? What route should i take?

This looks like mine... is the rebuild kit cheap cuz im not really wanting to dump $200+ on a new one thats probably made in china. If there is a rebuild kit for them where would someone source one from?

Thanks mike

Mike there are places that rebuild them. Do a Stovebolt search and see if one of the threads comes up.🛠

Check out chevyc60.com he has article on hydrovac

Well i think im gonna just get a new one so i have brakes for the time being, and keep my old one thats made in usa for rebuilding so when my new china made one goes out ill have a back up haha. I seen some stuff online about ppl running into issues with the rebuild kits not fitting right and being a time delay and i just want brakes now and ill find a kit that matches up right since ill already have a new one so ill have a remanufactured original as back up. But anyone got any reliable sources for rebuild kits for these boosters?

Thanks mike

Hey Mike,
Don't overlook the core charge. I think that will cost about $300 if you keep yours.
I would just buy it and slap it on and enjoy. Inquire into warranty.
I spent years worrying about parts on my restored cars and when I look back now I wish I was driving them instead. Just my 2 cents.
Only problem I have had with those units is surface rust on exterior. I had to remove a 2 month old one on my c10 and paint it. Was bare metal! My hand prints etched in rust! So hit it with some clear or silver or your favorite color!
Mike

Mike, also looks like MC is included. I think that is a deal if it is a direct replacement.
Mike

Hello i did see the chevyc60 article and found the reman inc whom remanufactures the cores so they will be the spot ill call for a rebuild kit assuming napa can get that new one for me.... just got off phone with them they said its coming up as obsolete but he ismcalling his distributor and they will call their parts supplier and see if one is still available.... why do i always run into issues like this with parts haha. I see ppl driving 1940s and below vehicles and i always wonder where the heck do they get parts at if i cant even get a simple brake booster for a 1972...

@lightningtruck what do you mean mc is included?

So in the event that napa cant get this new brake booster is there other "upgraded" options i can go for better braking, that might be available and not need to much riggery to make everything work properly and safely? as i have truck loaded at times wieghing in at about 20,000lbs... (5 ton of material).

In the future when my stove doesnt have so many irons in it i have a 1966 c60 front axle 10 lug with the wider brake drums that i got from scrap yard that id like to install for the extra braking power cuz i dont believe in overkill when it comes to stopping a heavy load and i figured having that extra half inch or so of drum and brake shoe to stop should make a differance for my front brakes.

Also when the stove space clears a bit, i have power steering pump and gearbox id like to install for even more safety upgrades cuz these old rigs need them with todays amount of ppl on the roadways. its not fun driving this rig in heavy traffic. Now when your on a back country road not seeing another driver it just feels like home for the truck in its original 1972 safety regulations haha. if i ever had someone pull out in front of me "knock on wood" and i was loaded they would be crushed like a can cuz she aint stopping for a bit when loaded fully and i aint swervin lol thats how more ppl die.

Ok so napa is a phoney they just have that on their site for looks haha. They cant get anything for any power brake boosters so im dead in water at this point... so what other routes are viable at a resonable price for brakes?? Im not really wanting to wait for a kit to then spend more time rebuilding it, got few things im needing truck for... any input on options would be great...

Thanks mike

Ed strain website had info on boosters in the past.
I used to own a '42 G506 and I think Vov (Vehicles of victory) had some booster info too? Maybe all older than yours though.
Anyway, I meant it included the master cylinder, sorry.
Lots of good info on the web about retrofitting brake parts.
Hydroboost is very popular.
I think we all run into the parts availability issue, lol, you just don't see the broken down ones on the road. Hehe
Mike

Gotchya i would have never guessed master cylinder... ha but i dont need a new MC as i have replaced that when i first got truck it started leaking into driver floor board but i was able to get that no problem. I just got off phone with orileys and they might have one suprisingly, a1cardone brand which ive seen before but crazy that they actually might have one over napa. They put in a customer request for one and will call back
and let me know when they can have one in. Hopefully they can get it cuz i hate the parts hunt. And i have so many things i need to do with truck right now its crazy this had to happen now. But thats usually how it works for me haha.

Anyway i have done a search on the 518061 part number for the one i seen on napa and found more.... i found one on ebay that is a 518001 part number.... anyone know the differance between these numbers as the part looks the exact same.

Typed in your 518061 number on Amazon and got this link...

https://www.amazon.com/s?k=518061+hydrovac+booster&ref=nb_sb_noss

Mike B

Wow now thats a deal!!!

The only numbers i can find on mine are "remfg kv b5" in yellow stamped. So mine is already remanufactured.... so im not 100% that part number is correct but it sure looks just like mine same ports/mounting and everything.... but that price is hard to beat soni might just order it and see if it works cuz amazon is pretty good with returns if it dont work....

What is the differance between the 518050 and the 518016 becides price and the second bleeder closer to the canister... where on mine its blank like the 518016.... i wouldnt think that extra bleeder screw is worth the extra 30ish bucks but who the heck am i becides a diy guy lol...

So after looking at other guys thread with same issue as me at same time. haha. i notice "3b" said that the length or width however the measure goes has to do with the number of wheel cylinders you have.... where did this information come from? Sounds like what i need to read up on.... anyway i believe i have 6 total wheel cylinders, dual rears and single fronts but i believe the spare c-60 front axle i have with wider brakes that i want to swap in eventually has dual cylinders on it so would it hurt me to upgrade to the 8 total wheel cylinders booster or would their be to much pressure build up since i only have 6 wheel cylinders at the moment.?.?.?

Thanks mike

The number of wheel cylinders is important because of the volume of fluid that needs to be displaced to move them all while maintaining a reasonable pedal travel and force. If you add 1/3 more volume by adding 2 more cylinders, it has to come from somewhere. Its possible it would work fine, its also possible that you would wind up with way more pedal travel to the point of making it difficult to drive.

A thought on the topic of your axle swap to get these two cylinders, you might check to see if the bigger brakes would fit on the current axle, saving you the trouble of changing the axle itself. I would be taking the "new" brakes all apart and rebuilding them anyway, it would not be much more trouble to yank the old brakes and check the fit. I don't know if they would or not, just a thought as many times things like that are possible.

Well that c60 axle is a slightly thicker axle and it also has 10 lug instead of 5 lug like mine. so id rather just swap it in then tear apart both axles just to swap brakes. i could just upgrade the whole front axle, brakes, and all....

But anyway back to the booster delima, is there a differance between the 518016 and 518050 boosters becides the extra bleeder closer to canister????

Thanks mike

Hy Guys, okay I am going to wade into this discussion. To answer the question about the differences between the two part numbers quoted, 518050 has 5/16" inlet and outlet hydraulic ports inverted flare and the unit is 18 3/4" overall length the cylinder is 12 3/4" in diameter. 518016 has a 1/4" inverted flare inlet port and a 5/16" inverted flare output hydraulic port, the unit is 16" overall length and the cylinder is 11" in diameter. DIY.MechanicMike which set of specifications better match what is on the truck now, if neither match please give us the specifications of what you have now. Hope this helps.

How do you take the measurements ???? These are the three part numbers i have found on the hydro vac power brake boosters... they all look just like mine but the 518050 has the extra bleeder closest to canister. Im so confused on what is what and my parts ppl around me arent helpful.....

And other funny thing i just notice, one on my truck the inlet and outlet brake lines are 5/16" like the 518050 but i dont have the second bleeder near canister.... so im all screw up now.... how do you take the "cylinder diameter" measurements like this spec sheet gives cuz thats only info left on spec sheet that im not 100% on.... im leaning toward giving the 518050 a try and just take the extra bleeder as a bonus cuz everything else is a direct fit according to spec sheet measurements but the overall length is hard to measure cuz the 18.75" and 19" is hard to differ when you dont know exactly how to measure it... im just laying on my back in gravel with a tape measure eyeballing cuz its not a flat surface to measure length haha but i k ow for darn sure its not the 16" one so ill scratch that off....

Hy DIY.MechaicMike, Choose the one which matches the one you have on your truck, if yours has 5/16' inverted flare piping on both ports and the overall length is the same then that is the one you want and it will be the easiest install. I think you are letting yourself get worked up over nothing, choose the one which matches what you have and order it, good luck.

Well im just wondering what the extra bleeder is for really? But i already got it ordered. i need brakes my truck is loaded with tree debris right now and i need to drive 15 miles to dump it haha and with no brakes thats a no go so thats why i was a lil worked up on trying to figure it out. Didnt think fixing simple brakes like these would be such a deal. But i would like to know how to find more info on these different types of brake systems for when i want to add the c60 axle with bigger brakes and 2 extra wheel cylinders i got.... hopefully the one i got is gonna work good.

Now with the booster with two bleeder screws which do you bleed first when bleeding the system? Or does it matter?

Hy DIY.MechanicMike, you bleed the one the greatest distance from the ground first then the other one. Usually the one closest to the diaphragm first and then the one on the barrel. Without seeing a picture that's the best way I have to describe it, good luck.

If one is handy, the whole thing can be bypassed and have brakes, just require more leg power, test out to get used to new leg power.

Ed

Mike, you have a Private Message

Heres a picture of my workshop with the big rig pulled in, it barely fit threw the garage door. Haha jk. I sure wish i had a shop to pull it in so i could do alot to it over winter when its cold and wet......but im a poor boy mechanic haha..... eventually im gonna paint it, havnt decided a color yet, was thinking white cuz its cheap and not as much heat build up cuz i dont wanna park it under a tree like the previous owner... and i also wanna paint the bed and the under carriage. there is alot of grease build up on frame almost like someone greased the whole undercarriage. which to be honest i think preserved everything from rusting, cuz the spots that i cleaned are rusty now so i gotta either paint it or re grease everything i "cleaned" ha jk. But it might be a super secret hack to rust prone climates like the mid west, just grease the whole truck grease fittings, frame rails, everything, f'it put some grease in a paint sprayer and hit the whole under carriage with a light coat lol.

Update: the previous order i made was canceled so i had no other choice but to contact midwest remanufacturing out of bedford park, il basically chicago. And they rebuild these and they didnt have one in stock for my truck but they said to send it in and we can have it rebuilt in a couple days so ...... you can guess who im doing business with. Its a 200dollar rebuild fee plus you have to ship it to them so depending on how far away you are its not half bad im luckly on the south tip of illinois and theybare at the top so shipping wont eat me alive. But figured id lay it out there for anyone needing same thing.....

Check with Reman.Inc.