Community Forums

Jpownell · 10-12-2019, 10:03 PM

Here’s the good news. I’ve got new rotors, new ceramic brake pads, rebuilt wheel cylinders, new rear shoes and related, and I was able to resurface my existing rear drums. My brakes work well in normal traffic on a flat road at reasonable speeds. About 50 miles on them before I took the Revcon for a trip.

On a long grade down, approx 6%, to the desert floor in Borrego Springs, my front brakes overheated and I lost power assist pressure. Fast forward, the rubber vacuum line from the manifold to brake booster looked fine but was blocked. Brake shop initially said I may need a new power booster!! Nope. Three foot of new rubber and I now have power assist back.

Today I’m driving around running errands in the Revcon. Fairly small downhill residential street. And I still overheat the the fronts with a gripping noise.

I ordered a new PV2 proportioning valve today. Want to do the brake lines also. I’m thinking I might have the same problem in the rubber brake lines that I did in the rubber manifold vacuum to the power booster. Things are blocked and preventing pressure flow.

Any suggestions?

Does anyone have any links, recommendations or experience to share with part numbers and thoughts on either/both rubber and metal brake line replacement? Front and rears.

I didn’t see any brake line info on the old Revcon parts list that used to float around on Google+.

Thanks in advance !!

Jeff

wimpy · 10-13-2019, 10:46 AM

I posted this back in April. It is under Tech Info heading & I think covers your issues.
Get back if not.

Quote:

Originally Posted by wimpy

Here's my 2¢, based on bringing 6 vintage cars & RVs back from the semi-dead.

Resurrecting a vehicle in storage for 10+ years. This deals primarily with brake issues.

Step on the brake pedal a couple of times to check the pressure. If the brake pedal is too soft, this indicates lack of pressure, which can be caused by a faulty master or wheel cylinder or other leakage.
Check the brake fluid level. If there's no evidence of leaks in the reservoir, wheel cylinders, or lines, chances are you've got contaminated fluid.
Inspect the brake lines for signs of leaks, rust, or corrosion.

After eliminating master cylinder & wheel cylinders as faulty and ensuring all the metal lines are intact & not rusted, you can concentrate on the other hardware & fluid. If the vehicle was exposed to road salt, you should probably plan on replacing the metal brake lines. The rubber brake lines have a life of 6-8 years. Replacement can be relatively inexpensive if you live in a metro area. You will need a flare nut wrench set (<$20) & some PB Blaster and maybe a pair of ViseGrip locking pliers to remove the brake hoses & lines. Take lots of pictures so you have before & after results & in case you forget what went where/how.

If you are planning on doing your own repairs, you should be aware of safety issues. Use the proper lifting jack & always support with a proper capacity jack stand before you get under the vehicle.

Brake fluid is hygroscopic! Your brake fluid has been absorbing water every day since it was put in the vehicle originally. All the rubber has been deteriorating internally since it was installed. SO:
1. Flush the brake system until you have clean fluid exiting the bleeders.
2. Remove all the rubber brake hose & get someone like Royal Brass & Hose or Pirtek to duplicate what you have. I've used stainless braided hose.
3. Check all the metal brake lines & replace any that are questionable, you will want to use a cupro-nickel line which won't rust like steel
4. Remove the brake cylinders & either replace or rebuild based on what you find and your ability & level of expertise.
5. Rebuild or replace the calipers.
6. Once everything is new/refurbished/rebuilt buy some Castrol Dot 4 Brake Fluid (formerly Castrol LMA) which you should plan on replacing by flushing every 2 years.

Remove all the engine hoses & belts & replace them.

This website will be your friend: https://www.restore-an-old-car.com/o...lectrical.html

Plan on replacing your rubber fuel lines. Dependent upon the fuel that was in the tank you may not need to have it cleaned. E10 absorbs water & rots older rubber fuel lines and can create rust in your tank. You probably will need to drop the tank & inspect. If it has an intank fuel pump replace the filter & dependent upon your budget, replace the pump as well.

In 2007, I drained a RR tank that had 25 yr old gas(it looked & smelled right-I think it was a high-test fuel from the early 80s) which I dumped into my late model Lincoln with no issues. E10 will be a different story, it's just nasty stuff.

I use ethanol free fuel in anything built before 1995.

BJohnsonsv · 11-17-2019, 10:34 PM

Quote:

Originally Posted by Jpownell

Does anyone have any links, recommendations or experience to share with part numbers and thoughts on either/both rubber and metal brake line replacement? Front
Jeff

Here are links to the R/L rubber brake links I used for the fronts. I also had a new metal line bent up for the front by a local shop for a very reasonable price (under $100).

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I have not yet replaced the rear rubber line (there is only 1 that T's into the metal rear line).

Good luck!

wimpy · 03-02-2020, 09:27 PM

Were you able to resolve your brake issues?

Jpownell · 03-03-2020, 11:11 PM

Thanks for asking. So here’s what I did that got me satisfied.

Replaced the rubber lines in front and rear with nice fabricated stainless steel flexible lines. No more rubber in the brake lines.

Ditched the horrible stock caliper and off the shelf pads with dual caliper heavy duty Wilwood 120-10963 calipers and Porterfield Enterprise performance friction D52 super friction racing style pads. A little noisy at times but great grip.

Replaced the simple booster check valve. Sometimes seems like I don’t have enough reserve vacuum at idle still but the power booster is working well. I haven’t figured out how to create more vacuum at idle except to give it more rpm.

Porterfield Enterprise in Orange County CA also custom made me some heavy duty shoes for the rear which I have not installed yet.

Now I’m cruising! Back down to the desert floor with no problem!

Jeff

thedjjack · 03-04-2020, 12:49 AM

next up grade ditch the vacuum booster for hydrovac booster... runs of power steering... you can get them out of GMC pickups 2000 and newer... and all diesel pickups...

solve your idle vacuum needs...

BJohnsonsv · 03-05-2020, 09:00 AM

Quote:

Originally Posted by Jpownell

Ditched the horrible stock caliper and off the shelf pads with dual caliper heavy duty Wilwood 120-10963 calipers and Porterfield Enterprise performance friction D52 super friction racing style pads. A little noisy at times but great grip.

Jeff

Fantastic! Were these bolt on replacements for the Olds (GM) calipers? What about the rotors?

BJohnsonsv · 03-05-2020, 09:04 AM

Quote:

Originally Posted by BJohnsonsv

Fantastic! Were these bolt on replacements for the Olds (GM) calipers? What about the rotors?

Actually, just re-read your earlier post (duh). Where did you get the rotors? Wilwood, too?

wimpy · 03-06-2020, 11:20 AM

Quote:

Originally Posted by Jpownell

Ditched the horrible stock caliper and off the shelf spads with dual caliper heavy duty Wilwood 120-10963 calipers and Porterfield Enterprise performance friction D52 super friction racing style pads.

Sometimes seems like I don’t have enough reserve vacuum at idle still but the power booster is working well. I haven’t figured out how to create more vacuum at idle except to give it more rpm.

What made the stock caliper horrible?

Have you done a cylinder compression check?

wimpy · 03-06-2020, 11:23 AM

Quote:

Originally Posted by thedjjack

next up grade ditch the vacuum booster for hydrovac booster... runs of power steering... you can get them out of GMC pickups 2000 and newer... and all diesel pickups...

Where is this vacuum booster located? Picture?

Jpownell · 03-06-2020, 10:46 PM

Couple things. Haven’t done a compression test. Not sure if that would impact my vacuum just knowing what the compression is, I’ve got a steady strong idle, just can’t capture enough vacuum sometimes. I’m open to suggestions like the one about the power steering.

Basically, I found that today’s off the shelf pads and rotors and calipers didn’t work for me. Tried different combinations and was never satisfied. Maybes today’s quality isn’t yesterday’s quality. I talked to the original owner of my Revcon and he told me a couple stories indicating the brakes were never the strong point on this vehicle, but he even towed a car and was satisfied. I wasn’t and I’ve never towed a vehicle with it and couldn’t image how hard it would have been to stop with the extra weight.

The Wilwood calipers and hand made racing type pads weren’t that much more than the “stock” parts. But what an improvement. What made the stock replacement calipers and pads horrible... my brakes didn’t grip well, and when they did under load they overheated quickly.

The Wilwood D52 dual piston caliper was a bolt in replacement except for a small clearance issue solved with slightly longer bolts in the hubs. This size was their standard early 70’s GM caliper replacement size. Still using the original style rotors but I would consider an upgrade to one of the slotted dense alloy racing style rotors if that would be as big an improvement as the pads were.

Hope that helps!

Jeff

LibertyRV · 04-02-2020, 02:43 PM

The interesting thing I found on my 76 250 is a large vacuum canister under the floor in the passenger compartment. Thing is huge and probably a couple “gallons” worth of volume. I think Revcon realized that they had a vacuum issue and made this addition to later rigs. I would love to hear more about your Wildwood brake upgrade. I feel that is one item I want to really do on our rig. I have the 19.5” wheels now and the front brakes look ridiculously small now. Running factory single piston calipers and stock rotors. Have you found in your research any of the big brake kits fit?

LETMGROW · 04-02-2020, 04:33 PM

Quote:

Originally Posted by LibertyRV

The interesting thing I found on my 76 250 is a large vacuum canister under the floor in the passenger compartment. Thing is huge and probably a couple “gallons” worth of volume. I think Revcon realized that they had a vacuum issue and made this addition to later rigs.

One of the reasons these vacuum reserve tanks were so large is because the heater and air conditioning controls, doors and vents were all powered by vacuum. When you went up a hill, pressed on the accelerator and the engine vacuum dropped off the loss of vacuum would let the doors close and shut the air flow off inside the cab. The added vacuum reserve would help offset this as well as create a reserve for the power brakes.
Lynn

LibertyRV · 04-02-2020, 06:58 PM

Quote:

Originally Posted by LETMGROW

One of the reasons these vacuum reserve tanks were so large is because the heater and air conditioning controls, doors and vents were all powered by vacuum. When you went up a hill, pressed on the accelerator and the engine vacuum dropped off the loss of vacuum would let the doors close and shut the air flow off inside the cab. The added vacuum reserve would help offset this as well as create a reserve for the power brakes.
Lynn

Interesting. I am converting the entire heat/AC system over to a Gen IV Vintage air system that uses servo doors so the only thing the vacuum is for is the brake booster now.