The Stovebolt Site Forums The Parking Lot Big Bolts 66 C60 getting Rid of the hydrovac for electric shift now need brake optio

Hey guys I'm tired of hydrovac problems so swithing to electric shifter on 2 speed rear end here is were I need you guys..... On my brake option does anyone have a great reliable swap with boost that mounts on firewall with master cylinder?????????????.......... I was thinking something from like 1991 chevy hd3500 something like that come on guys I know someones got a great swap give it to me please!!!!!!!!!!

HELP PLEASE

I haven't seen one done yet,but I'm researching an electrically-assisted,( '80's I.H.C. set-up),dual-reservoir brake system. I used to drive a couple of straight trucks,equipped with electric assist,and I like the system. This is a firewall-mounted unit,as well.The I.H.C.'s were drum all the way around. The hydrovac has nothing to do with your 2-speed.They both use the same "vacuum manifold",but the plumbing branches off from there. One line to the hydrovac,and one to the 2-speed shifter,(not sure where your unit is located).My unit is bolted to the transmission.There are 5 lines ,on the shifter. one from engine to unit,two,from the shifter,to the vac. diaphragm,the small line connects to the 2-speed adapter for the speedo,and one for atmosphere,(vent behind the seat,driver's side,exit). If I change my brakes,i'll keep my vac. unit,because it works well. What kind of isssues are you having?

every 2 yrs I have to get a new hydrovac ..... then everytime I change it I cant get brakes and I have ran over 10gals of fluid with my buddy in 2 days trying to bleed this girl and wont give me any pedal ...... so I bypassed hydrovac and got half a petal whats the deal its brand new and I have bleed the vac by cracking line under pressure 10 times fluid everywhere and the same for exit line to brakes and still no pedal Im just fedup completely fedup with it so I was looking at 81 C60 master cylinder with booster looks like it would work and then Im going to run a electric 2 speed shifter on my rear end........... I would keep my vacuum shifter if I had a way to power bleed but cant find anything on a power bleeder that works on this trucks master cylinder and I guess someone out here made one from the lid of the master but cant find the thread so I use my dump everyday for work and this is killing me

Your 2-speed works on vacuum-no need to bleed. no fluid,just air. There's a petcock on the vacuum manifold,that should be removed periodically,to check for blockage,due to condensation and normal build-up. This blockage could hinder the performance of both the hydrovac,and the 2-speed.System calls for between 18-21 P.S.I.,to operate correctly,(hydrovac spec's).Have you cracked/bled the wheel cylinders? any fluid? have you adjusted (All) the brake shoes? Have you replaced the rubber brake lines? They collapse from the inside,and will cut-off flow. We've been working on a '59 Viking 60 bus,with the same problem. P.O. parked it,after re-building the 261,installing a new hydrovac,and single-pot M.C. He couldn't figure the brakes out,so he GAVE it away!! Now it has a new dual reservoir M.C.,with booster,but still no brakes! Engine only produces between 8-10 P.S.I.,(vacuum),which is fine for an idle,but truck has virtually no power! Brake pedal is all the way up,and SOLID!! BAFFLING!! We bled the wheel cylinders,and fluid shoots 3',but brakes won't grab! Yeah,they're adjusted. I FINALLY got Billy W. convinced to replace ALL of his brake lines. We have our fingers BRAIDED! GOOD-LUCK!!

I use this pressure bleeder and have had great results using it.

http://www.motiveproducts.com/

I think you're on the right track with going with a later model MD power brake system. I have an 81 C60 and it was an straight forward job rebuilding and bleeding the brake system. The big plus is you can get any replacement parts at your nearest NAPA. The only issue that may come up for you is that the later trucks have dual (front/rear) master cylinder set ups. I don't know how your earlier truck was plumbed. Good luck.

Hy 66dump, if you have bypassed the Hydrovac and have bled all the air out of the lines and cylinders and still only have half a pedal, then your brakes need adjustment. There is a special bleeding procedure for bleeding a system with a Hydrovac, you must bleed the two Hydrovac bleed screws before moving on to the wheel cylinders. As others have mentioned there can be problems with the flexible lines collapsing from the inside. There is a simple test to check that the Hydrovac is functioning (when it is connected to your system), with the engine off pump the brake pedal a few times, now press down on the brake pedal and start the engine, if the Hydrovac is functioning the brake pedal should move closer to the floor under your foot pressure, hope that helps.

Going to an electric 2 speed is a step in the right direction. Electric as found on Ford, Dodge and International worked so much better when they were new than what GM used. And after 50 years, parts are hard to obtain and all vacuum shift does is set up a good place for a big vacuum leak. Hydravac wasn't all that bad. I have them rebuilt, use a pressure bleeder and they stop like a new one.

ok I got the pressure bleeder..... I tried adjusting brakes and I cant get them to move I thing I need new adjusters for both front and rear do you have a part number and/or place to pick them up at ......

also I think Im going to dump the sm465 and run a nv4500 5 speed any thoughts

I think you might consider doing one thing at a time. Any particular reason you want to get rid of the 4 speed?

Hy 66dump, for the brake parts you'll need to provide some more info to be sure of the correct part numbers, width of rear brake shoes, front axle size or bore of front wheel cylinders. As for the trans. I don't know if the NV4500 is strong enough for dump truck duty, plus you'll need to source a p.t.o. to run your hydraulic pump.

rear is 15X5 shoes I don't know what the fronts are I am assuming 1.5 bore as almost all 2 tons are.... as for nv4500 was thinking of getting that 5 gear for alittle more freeway speed without high rpm .... so really you don't think it could handle the dump 3B it has pto access on both sides just like sm465

Hy 66dump, does your rear brake crossover line run on the inside of the brake drum or on the outside of the backing plate. As to the transmission you will have to purchase a P.T.O. which is compatible to the transmission. I do not think the NV4500 was ever intended to be used in this heavy an application.