Auto Park Brake converted to Manual Lever

[the_dieter]

So they have a blue and a brown switch! AKA RBS & RBS kind of hard to tell them apart...this just gets better and better.

I am wondering if there is about 4" of space behind the actuator to place a secondary hydraulic cylinder. I sketched up a simple end cap substitute that incorporates the cylinder and it looks like the best possible solution.
(Grabbing myself by the collar to keep from rushing into a retirement destroying project!).

Best, Jack

PS: The wiring cleanup phase is coming along nicely and I am about ready to wire the switches.

[tropical36]

Originally Posted by iRV4FUN

They also make a Blue Switch!

WORKHORSE PRESSURE SWITCH W8001071

And this one does what on which of their systems?

[tropical36]

By Jerry Peck...
Regarding blocking the air flow in the engine compartment, the heat shield I had in mind making was just have separated the air flow between the master cylinder and the engine manifold, not box in the master cylinder.

Yesterday I got back to it and have installed your/my heat shield, using some scrap alum. siding. Not a lot of room in there, so not double wall with insulation in between, but has to be worth something. Thing is, will we ever really know?
I had to stay forward more than I would have liked to provide clearance for #1 spark plug, but not a bad install and it does also provide for a shield between the manifold and the brake lines as well, which is also suspect for heat absorption.
Back to #1 plug, I find the plug's heat shield dangling on the wire with the reason being a broken manifold bolt which it is attached to. Real nice, but thinking it over, the cure would be much worse than the disease and at worst so far, is sometimes a slight ticking sound. Don't even hear that now and just put it back in the hole and used a piece of wire to hopefully hold it there, before discarding it altogether and take my changes with wire burn. I think not too likely concerning #1, though and for now, I'm good.

[JerryPeck]

Originally Posted by tropical36

Yesterday I got back to it and have installed your/my heat shield, using some scrap alum. siding. Not a lot of room in there, so not double wall with insulation in between, but has to be worth something. Thing is, will we ever really know?
I had to stay forward more than I would have liked to provide clearance for #1 spark plug, but not a bad install and it does also provide for a shield between the manifold and the brake lines as well, which is also suspect for heat absorption.

Glad you are working on yours, I'm not going to be able to even attempt to get to mine for another couple of weeks. At least I now know that was the likely cause of my/our brake problem after long distance, slow speed, in town driving.

Being as you found the room so tight between the master cylinder and the manifold - just no room for the heat to dissipate before reaching the master cylinder.

May need to do what you jokingly (I think jokingly) suggested: install a fan to continuously blow on that master cylinder to keep it cool.

That installation sounds worse than on my '83 Jaguar XJS V-12, the master cylinder is (of course) in the engine compartment, and it gets much to hot in the engine compartment ... I can replace the brake fluid, bleed fresh fluid down to the front brakes, and within a couple of weeks the fluid is dark and burnt looking ... the heat in that cramped and tight engine compartment is unbearable. The difference between an 80ish degree day outside and a 90ish degree day is significant in the amount of heat which builds up in there, much more than the 10 degree difference in outside temperature.

Maybe I can get one of the fuel line coolers used to cool the fuel line and install it in the motor home to cool the brake line?

[tropical36]

Originally Posted by JerryPeck

Glad you are working on yours, I'm not going to be able to even attempt to get to mine for another couple of weeks. At least I now know that was the likely cause of my/our brake problem after long distance, slow speed, in town driving.

Being as you found the room so tight between the master cylinder and the manifold - just no room for the heat to dissipate before reaching the master cylinder.

May need to do what you jokingly (I think jokingly) suggested: install a fan to continuously blow on that master cylinder to keep it cool.

That installation sounds worse than on my '83 Jaguar XJS V-12, the master cylinder is (of course) in the engine compartment, and it gets much to hot in the engine compartment ... I can replace the brake fluid, bleed fresh fluid down to the front brakes, and within a couple of weeks the fluid is dark and burnt looking ... the heat in that cramped and tight engine compartment is unbearable. The difference between an 80ish degree day outside and a 90ish degree day is significant in the amount of heat which builds up in there, much more than the 10 degree difference in outside temperature.

Maybe I can get one of the fuel line coolers used to cool the fuel line and install it in the motor home to cool the brake line?

Don't think we'll need the aux. fan and actually found the MC to be somewhat forward of the exhaust manifold with the lines coming from it a lot closer. As for tight, not all that bad I guess. Now, I could pull it back out, find some thin hard type insulation to sandwich in between more metal, but then possibly another problem. I had to build this thing pretty high from the frame to actually get up and above the MC and by this time there were pump lines present so my shield has a curve in it to compensate, along with no sharp edges. For mounting I removed the wiring running along the top of the frame and tied it to the brake lines out of the way. Then used the same wire holder hole to install a long holding screw with a nut both under the shield to keep it there and then down under with another, holding it to the frame. It's also bent over the inner part of the frame so as not to move around with just one screw holding it. Used lock tight on the bottom nut, as well. Don't think it's going anywhere anytime soon.

[the_dieter]

Status update on parking brake warning lights and buzzer:
Wiring needed to be cleaned up in front of the firewall before even starting with the new wiring. Before and after photos show what I have done. A major item was getting access to the power steering reservoir which is now visible.

Now I am ready to do the new wiring.

Best regards, Jack

[tropical36]

Status update on parking brake warning lights and buzzer:
Wiring needed to be cleaned up in front of the firewall before even starting with the new wiring. Before and after photos show what I have done. A major item was getting access to the power steering reservoir which is now visible.

Now I am ready to do the new wiring.

Certainly looks a lot better.

[JerryPeck]

Originally Posted by the_dieter

Status update on parking brake warning lights and buzzer:
Wiring needed to be cleaned up in front of the firewall before even starting with the new wiring. Before and after photos show what I have done. A major item was getting access to the power steering reservoir which is now visible.

Now I am ready to do the new wiring.

Best regards, Jack

Originally Posted by tropical36

Certainly looks a lot better.

Agreed.

[TitanicPilot]

Originally Posted by the_dieter

I agree that the RGS could give more advanced warning because of fluid leaking into the electrical section. My problems with the relay, solenoid, etc. were sudden so I don't suspect the RGS. When I replaced the RGS as a precaution, I dissected it and did not see any evidence of oil on the contacts.

I made it a practice to check the fluid level and also look for any signs of leakage around the RGS electrical connecfor before starting on a trip with the motorhome.

Since I have designed pressure switches, solenoid valves and hydraulic equipment for a living, I know what to look for.

Best regards, Jack

With your design experience and insight from dissecting the RGS, perhaps you could figure out a way to replace it with some off the shelf plumbing components and an industrial grade pressure switch. Result: bulletproof RGS capable of outlasting the coach.

[4Knights]

Originally Posted by TitanicPilot

With your design experience and insight from dissecting the RGS, perhaps you could figure out a way to replace it with some off the shelf plumbing components and an industrial grade pressure switch. Result: bulletproof RGS capable of outlasting the coach.

I'd buy that!

[JerryPeck]

Photos of the proximity of the exhaust manifold, master cylinder, and brake lines.

Also photos of heat shield I installed today.

I looked at the parking brake setup on the left side of transmission again today to check the practicality of fashioning a solenoid activated lever to hold the parking brake in the released position while driving. Might be a bit of a problem to make it work here.

I need to look at the parking brake pump and actuator next to compare the practicality of installing the parking brake safety hold-out device there to installing it up by the transmission.

First to create the simple operating solenoid actuator: activated by a switch at the dash. Once I get it made and operating, then will come the challenge to making it automatically operated above 10 mph so the parking brake will not lock-up at speed when the system fails (looses pressure, cooks a wire, etc.).

Problem is that it will probably be about a month before I next get to work on the motor home.

[tropical36]

Jerry...
Looks good and similar to mine except your shield might extend further back and mine is a lot higher and sorta curves to the outside, up and over the MS, but can still easily check the fluid from under the fender well. Don't know why, but your MS looks like it's sitting further back towards the manifold than mine. Must just be the angle as I can't see how there would be a difference. Even so, what year is your chassis?
Let's hope we accomplished something here and will we ever know for sure?

[JerryPeck]

Originally Posted by tropical36

Even so, what year is your chassis?
Let's hope we accomplished something here and will we ever know for sure?

Mine is a 1998 I believe - I need to look up the data to know for sure, but this afternoon I took it back where we keep it parked.

Did we accomplish anything? Hopefully, we will never find out that we did not.

I made my heat shield low enough so I could check and fill the brake fluid from above - but I suspect it is not going to be easy. I did double hem the top edge so I would not be cutting myself up reaching over the heat shield.

I made my heat shield 16 inches long, the front end is mounted through a frame hole where there was an unused cable tie-off I removed to expose the its hole. I could have made it another 3-4 inches longer toward the front to another unused frame hole, but then the heat shield would have been rubbing against cables and other things - I did not want to start moving all those things, so I kept it back from them, but far enough forward to be completely between the exhaust manifold and the master cylinder. Plus I figured I would need give the air room to get to both sides of the heat shield.

The back of the heat shield is bolted through a hole I drilled through the flat bracket which goes from the frame to the floor supports.

[the_dieter]

I haven't looked into a replacement switch for the RGS, probably because I didn't have a leakage failure. I only dissected one out of curiosity when I replaced mine as a precaution.

The RGS has a metal diaphragm and the body is roll swaged together which I think compresses the seal. If the seal leaks, it will go into the electrical section and out through the connector.

Subsequently whenever I started on a trip, I looked for any signs of leakage around the connector when I checked the fluid level. I could never tell what the fluid level was using the mark on the reservoir so I always unscrewed the cap and looked in. I think I always had the reservoir slightly over filled to overcome another defect in the system (too small a reservoir) . Thankfully, mine was in front of the firewall and I feel sorry for the folks that have it under the floor.

As far as finding a replacement switch goes, it may be more practical to just replace the switch every 15,000 miles with a new one as some have done because there are so many other failure modes in the system that just getting a reliable switch will not make it foolproof.

Any failure in the electrical circuit that powers the solenoid valve which holds hydraulic pressure against the spring will allow the APB to lock up, whether the coach is moving or standing still. This can be due to a relay, fuse, short circuit or melted connector on the ignition switch. I think the relay and melted connector happened on our rig.

Workhouse sells an ignition improvement kit to upgrade the ignition power connection through a relay to make up for the fact that some coach builders put too many accessories through the ignition switch. I put that kit on mine but may not have needed to now that the APB has been removed...oh well.

Best regards, Jack