Packard Forum Index » V-8 (1955-56)

Recently noticed that brake lights weren't working on the Patrician. Got a replacement from Napa for the Wells RB402 brake light swith (Echlin PN SL159) and installed it. Brake lights worked and went out when pedal released but appeared to have no load leveller. Further checking was interrupted by emergency at house and had to leave it for about an hour. Car had been down in the rear and when I returned about an hour later it had levelled. Got test light and commandeered neighbour to help. Power distribution to levelling system was correct and interrupted when brake pedal depressed and, although brake lights went out when pedal released - no power to levelling system. Checked again about thirty minutes later and, again, had power to levelling system. Sat on back of car and it levelled itself. Brake pedal is normal and all wheels spin, normally without drag, with car in air and no brakes applied. Entire brake system (including master cylinder and Treadle Vac) completely rebuilt, professionally, just over three years ago and, as I had to pull the rear hubs and axles to replace rear wheel bearings about a month and a half ago, went ahead and pulled the front ones and checked brake lines and wheel cylinders while I had the car in the air. Load leveller was working as advertised with the old brake light switch although brake lights weren't.

Any insights from anyone - am I missing something or am I just dealing with a defective switch? Brake lights come on and go off when pedal is depressed and released. Just takes about twenty to thirty minutes before power is restored to Torsion Level.

I'm thinking defective switch. Its job is pretty simple--supply power to the leveling system when pressure is NOT applied, diconnect power from leveling system terminal and apply it to brake light terminal when pressure IS applied.
Those two states of operation ought to be easy to check with a test light. Sometimes you can have everything hunky-dory in the brake switch department and have an intermittent leveling control box, been there, fixed that.

My Echlin catalog (not particularly new) doesn't list an SL 159, but shows SL 138 as the correct switch for the 55/56 Packards with T/L. The OEM switch (Packard #439841), Wagner Lockheed # FC-22052 is extemely rare to find, most having been ruined prematurely by conversion to silicone brake fluid. But there are several well-publicized alternatives including other hydraulic switches as well as a mechanical switch on the pedal arm.

I would also be suspicious of the switch as it may be overly sensitive to the residual pressure and not changing state instantly.

A couple of other possibilities if changing the switch doesn't help. Is the residual check valve keeping more pressure in line than the 5-10 psi it should or is the compensator port in treadle vac not uncovering properly allowing pressure to slowly bleed off instead of release as soon as pedal relaxed.

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I agree with HH56 comment above.
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Also, I believe that some Volkswagen brake switch is tri-prong with the same functionality (right, Keith?). One can also use a regular OTC 2-prong switch and a Radio Shack relay to duplicate the functionality. Someone up at NW Packards in PI sells a kit like that, IIRC, if you do not want to tackle the electrical circuit. I have this solution on my 55 Pat and mounted the relay inside the passenger compartment to keep it away from exhaust heat. It's still working after 5 years. I don't have the BTV either.
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Then, of course, there's the manual override DPDT switch, which can be used in conjunction with the auto system. There are many possible ways to wire this.
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There must be an earlier thread on this set of solutions or was that before PackardInfo?
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Craig

Current Napa catalogue lists Echelin PN SL 159 as replacement for Wells RB402 (Volkswagen) switch. I went out earlier this afternoon and put the old switch back on the car and Torsion-Level works as advertised. Must conclude that new switch is bad. Have another (Wells) one around here, someplace, still in the box. Will try to locate it tomorrow and try it but think I'll go with the two pronged switch and Radio Shack relay for permanent use.

Thanks folks.

Since you will also have to re-route some wiring if you do the relay, here is one mechanical option Craig mentioned if you don't want to mess with hydraulics at all. Several of us have this setup and it also works very well.

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HH56, thanks for the attachment. I'd have spent hours searching for it.

Not a problem. That is a photo of my 56 but IIRC, the 55 brake pedal arm is a bit different so the mount and dimensions as shown probably won't work on yours--but should be easily doable..

Let me commend HH56's mechanical brakelight switch to you. I have the relay installed in my 400 in conjunction with a mechanical switch. The GM mech switch is much simpler and it follows the KISS principle. I have already purchased that switch for my Carib.