Repo RS vacuum lines

[Dave69x33]

firstgenaddict,


Nice work! Many years ago I did some logo design, sign painting, and a small amount of pin striping.  Using a pin striping brush is a bit of a lost art!

Questions:
1.) What paint did you use, enamel from a hobby store (i.e. model paint)?
2.) Did you first clean the hose with alcohol or other cleaner to remove the red stipe or just paint orange over the red?
3.) Was it tricky to keep the new hose straight, and prevent it from twisting, as you pulled it thru?

The toughest task I had was removing and then installing the two vacuum hoses and grommet that go thru the fire wall to the headlight switch.  I had to remove the bolts that secure the power brake booster/master cylinder assembly to the firewall, pull and tie forward (away from the firewall) it with rope forward to gain access to the grommet hole. Prior to that, I had to disconnect the brake push rod clevis from the pedal.  I forgot how tight that space is to work in under the dash! 

I disconnected the old hoses from the switch and left them in the grommet and pushed and pulled the old grommet out of the firewall from the engine bay side. I used small zip ties along the hoses so they would not slip by each other.  I installed the new hoses in the grommet with a bit longer slack length, secured them with a few zip ties along the hoses, then pushed the grommet/hose assembly into the hole in the firewall from the engine bay side.  It took several hours to install the grommet in the firewall. I had to use a small flat blade standard screw driver to push the inside lip of the grommet thru the hole, as the grommet has lips to seal on both the outside and inside surfaces of the firewall sheet metal.   Its very tough reaching around and behind the brake booster and brake lines when the car is fully assembled. It was a much easier job installing the hoses/grommet during the restoration without the brake booster and front end sheet metal in place!

Has anyone done this RS hose replacement on a finished 1968-69 RS differently?  Is there an easier way without dismantling the front end sheet metal?

I thought about installing the grommet in the firewall then pushing/pulling the hoses thru the grommet; first applying something like liquid dish soap or Vaseline to the hose. 

Sorry for hijacking this discussion thread.  Perhaps this discussion belongs in the "Maintenance" topic category?

   
 

[Tinkerr]

I’ve found the hose installation is straight pretty forward on a assembled car. I’m going to tackle the firewall grommet as soon as my son is available for the under the dash work. I think it will be easier with people and he’s a hell of a lot more flexible.

[cook_dw]

Excellent work as always James.

[Tinkerr]

James, The techniques and tools you come up with to recreate the factory markings are nothing short of amazing.

[firstgenaddict]

I used orange one shot which I thinned way more than you would to pin stripe a panel.
It was not very difficult to keep the hose straight, however I had left the hose hanging from one end for a few days so it had no curl in it from the beginning.
I used a lab tower with clamps to hold the guide at head height and then without lifting the brush pulled as far as I could then, re-gripped without lifting and pulled the last 2 feet, there is IIRC a slight, 10%? fattening of the line at that point, however it is either under the dash or at the firewall grommet area and is not even noticeable when fully exposed and pointed out.

FWIW I take the hoses out a week before I am planning on doing anything with them... lay them out, organize, and then hang them on the wall or draped over something so they have a big lazy arc with the ends hanging. If they are allowed to relax and untwist from the coiling, they are much easier to get into a new position.
 
Easiest way- first the grommet and then the 2 lines through grommet-I think I used windex.

[Sauron327]

I've only been  doing this four decades. Fab work, mindless panel replacement, restoration, pinstriping and hand lettering. Not a big deal. I guess the cars on the the cover on Muscle Car Review I've done do not count. Nor does the owner who is my best friend who owns over 50 cars not including historic flop top cars. He is a real gearhead who understands mechanics and paintwork. Chuck Fisher. Last name Fisher by the way.

HOK makes a lettering and striping paint also. I've only been using that for ten years or so. I like it for certain jobs. Buy some brushes and see if you have the ability to do it.

[Tinkerr]

I have a follow up question. If you guys will indulge me. When the vacuum lines travel down the front of the core support to the canisters do they route down and around the frame horns or on top of the horns between the inner fenders? Thanks

[Dave69x33]

Tinkerr,

I am still working on my '69 RS headlight system, testing the components, and trying to get my system to work correctly. I'll post pictures how I routed my hoses to the actuators within the next few days. 

To answer your question, the RED and GREEN actuator hoses do route down and secure to the front of the core support with a plastic retainers. See item 2 #3830786 called out in the '69 AIM Z22 RPO option Section B6. If you don't have the retainers, the base of the retainer pushes into the hole in the core support, wrap around the hoses, then the tip of the retainer pushes in to the base of the retainer.  I used small wire ties along the hose to help keep them together until the hose were secured in the retainers.  I left the wire ties on for a few days until the hoses warmed up and conformed in position as everything is a bit stiff - here in Indiana it's still cold in my garage!  The hoses then route between top of the frame extensions and bottom side of the inner fenders.

BTW...I took apart a repo vacuum relay and an old headlight switch to see exactly how these components work to control the vacuum signal. I will post pictures of these components in the next few days.  All told, I believe the 1969 AIM covering the how the RED and GREEN hose connected to the vacuum relay is incorrect.  When I reversed the hose to place the GREEN hose on the top "R" and place the RED hose on the bottom "G" port, my headlight system "attempts" to function correctly. I need new actuators as my original units leak too much vacuum to fully open and close the headlight doors.  I also found that the "over center" springs that help hold the headlight doors open and closed are very stiff. If an actuator will not hold strong vacuum (old leaky seals), the vacuum force cannot overcome the spring and the door may only start to open, or only partially close.  I believe this is the situation with my actuators. If I pull a door 3/4 of the way open or closed, it will finish its travel.

If you review the RS hose routing in the 1968 AIM, the GREEN hose connects to the top port and RED hose connects to the bottom port on the vacuum relay. The GM parts books call out vacuum relay GM#5638498 for 1968-69  All, Sup #5638272.  The superseded part number 5638272 may have had the R and G ports opposite those on the newer 5638489 relay.  After bisecting my vacuum relay and studying how it works, the GREEN and RED hose must be connected as instructed in the '68 AIM: GREEN on the top port and RED on in the bottom port.
   

[Tinkerr]

The hoses then route between top of the frame extensions and bottom side of the inner fenders.

That's what I needed to know. I couldn't discern that from the assembly manual. I've been having a issue with the relays. I have a original vacuum relay that functions well, but really looks like HELL. I purchased a OER relay that doesn't work. I have another relay on the way, will see if that works. The relay ports are labeled R on the top port and G on the lower port which coincides with the assembly manual and information sheet included with the repo hoses.
Thanks for the reply. Paul

[Dave69x33]

Tinker,

Who did you purchase your newest vacuum relay from and do you know the brand?  I need to replace my original vacuum relay as it will not "relay"more than about 2" of vacuum to the actuators. I would like to know if your new vacuum relay works well.

Testing A Vacuum Relay: 

With my engine at idle producing 9" - 10" of vacuum, I used a vacuum gage and found that only about a 2" vacuum signal was being supplied to the actuators from the relay.  I verified that I had a full engine vacuum signal to the relay via the back hose from the check valve to the T-fitting that connects to the YELLOW hose that is spit between the reserve tank and the Y-port on the relay.  I was glad to see that my vacuum reserve tank will hold the 9" -10" vacuum without any leak down.  At that point I tested the R-port and G-port on the relay to confirm that the relay is functionally bad.  I expected to see full engine vacuum through the relay to the actuators.

I recently cleaned 50+ years of debris that got sucked up and stuck to the control valve. After using foam engine cleaner and warm water to flush the debris, I used a digital bore scope and tooth picks down the R, Y, and G ports to clean around the valve and walls. Tried my best to salvage the relay; the diaphragm in the relay still works and will hold vacuum (tested with a Mityvac gun). The relay responds quickly to the vacuum signal via the ORANGE hose from the headlight switch. My vacuum relay still looks very good but unfortunately vacuum is leaking past the seal diameters that control the direction of the vacuum signal between the R and G ports.

I have an older repro vacuum relay that did not work well. I took it apart to better understand how it works.  I'll post some pictures with an explanation how it works that others may find helpful. I also took an old RS headlight switch apart to clearly understand how it works.  My headlight switch would not transfer the vacuum signal to the relay and now I now understand why.

[rich69rs]

Who did you purchase your newest vacuum relay from and do you know the brand?  I need to replace my original vacuum relay as it will not "relay"more than about 2" of vacuum to the actuators. I would like to know if your new vacuum relay works well.

I had to replace my original relay last Aug.  I purchased an OER reproduction relay from Classic Industries and it works very well.  Both doors open and close together, quickly, with no hesitation or intermittent movement or hesitation.

Richard

[Dave69x33]

Thanks Richard.  I'll purchase the same OER relay.

I also need to replace both actuators as neither one functions well.  Like my relay, the actuators are the 50+ year old originals.  The piston seals must be hard, cracked, and leak vacuum. I tested their function with my Mityvac. The piston rod will move about an inch or less then stops. I spraying Boeshield T-9 in them to lubricate and try to get the piston seals to work but that did not help.

All,

Here are a few pictures of the internal components in a typical 1968-69 on the vacuum relay that show how they work.

[Dave69x33]

A couple more views of the vacuum relay internals.

[rich69rs]

I also need to replace both actuators as neither one functions well.  Like my relay, the actuators are the 50+ year old originals.  The piston seals must be hard, cracked, and leak vacuum. I tested their function with my Mityvac. The piston rod will move about an inch or less then stops. I spraying Boeshield T-9 in them to lubricate and try to get the piston seals to work but that did not help.

In 2005, after I had completely disassembled/rebuilt the front end of the car, sub-frame, engine, trans, etc., and was then in the process of re-assembly, one of the decisions I made then was to replace the vacuum canisters.  My originals were still working and I wasn't aware of any issues at the time, but my reasoning was that they were 36 yrs old at the time and that it was only a matter of time before I would have an issue and there was no better time than now to replace them. 

I had a couple of issues with the repros. 

1.  Mounting to the existing bracket was an issue requiring a minor bracket adjustment to accommodate the new canisters. 

2.  Connecting the vacuum hoses to the canisters as per the originals resulted in the canisters (and hence the headlight doors) operating backwards, i.e. headlight switch pushed in, doors would be open.  Pull headlight swithc out, lights would be on, doors would be closed.  This was aggravating but an easy fix - I simply swapped hose connections on the canisters and everything worked fine.  Canisters and hoses are covered by the gravel shields and aren't visible - so the hoses being swapped from original is not visible unless you drop the gravel shields.

That was 17 years ago and I have no idea as to whether or not this is still a potential issue.  A lot has probably been fixed, improved since then.  Just mentioning it FYI.  As an aside, the repro canisters still work fine - I haven't had any issues with them once I installed them with the mods mentioned above.

Thanks for the pictures of the disassembled relay valve.  I still have my original one and plan to dissect it as well - just haven't gotten  around to it yet.

Richard

[Dave69x33]

And illustrations that explain how the relay works.