Hydraulic Brake Light Switch

TFB

TFB

Member
I was recently researching parts and came upon this negative product review for a hydraulic pressure switch for a brake system. It carries a very reputable name... ACDelco, but who knows if it's genuine or a knock off. Many parts are that way anymore.

Here's the part link
https://www.amazon.com/ACDelco-U855-Professional-Brake-Switch/dp/B0012OZO1I/?tag=atomicindus08-20

Since I'm in the process of overhauling a '39 setup on a '35, it got me thinking about this potentially weak link in the system. I know there's been countless discussions about single vs. dual systems, and the safety factor in redundancy. But this switch seems to me to be a big problem. They all seem to be made the same way, metal housing with a plastic insert that's then crimped over.

I've decided to try a '67 mustang MC setup which would be better if I used a pressure switch and had a failure I'd still have half a system, but I was wondering if anyone has used or knows of a conventional mechanical pedal switch setup that available? I don't know when Ford switched to that type switch but maybe that would be a better option. Thanks for any input.
 

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Use the Harley Davidson hydraulic switch. They operate on low pedal pressure and last a long time. Do a search on Fordbarn.
 
use a Harley Davidson switch, they are 1/8 pipe thread, same as early Ford, they come on as soon as you touch the pedal
 
Thanks for the comments, but I guess I didn't explain myself well.

I've also researched the Harley Davidson hydraulic switch, and yes 1/8"npt like the original. However I have found reports of issues with them also. Not exactly like the issue described above, but it's basically the same manufacturing method.

The main point of the thread was my concerns is with current manufacturing quality, and trying to move away from a hydraulic switch.

With parts made all over the world we've all have had experiences with shoddy parts.

However this isn't about the fitment of a trim piece, I'm basically talking about a plastic plug which is crimped in, over time fatiguing and blowing out.

Now maybe it will start to leak, and if noticed, it can be changed, but in the case above, he wasn't so lucky.

Does this point of failure give anyone else pause for concern? Or is it just me?

I mean, isn't this the way the story always goes??? Thousands invested and a lousy twenty dollar part put him in a ditch... or worst.

I've looked at Speedway's Brake Pedal Assemblies to get an idea of how they address the issue, but their pedals, which are made by TCI don't have switches, so I guess they use piped in ones as well.

I guess I could use some type of Lever Roller micro switch used in industrial applications

So any thoughts or experiences or pics of a spring loaded pedal switch install?
 
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TFB said:
Thanks for the comments, but I guess I didn't explain myself well.

I've also researched the Harley Davidson hydraulic switch, and yes 1/8"npt like the original. However I have found reports of issues with them also. Not exactly like the issue described above, but it's basically the same manufacturing method.

The main point of the thread was my concerns is with current manufacturing quality, and trying to move away from a hydraulic switch.

With parts made all over the world we've all have had experiences with shoddy parts.

However this isn't about the fitment of a trim piece, I'm basically talking about a plastic plug which is crimped in, over time fatiguing and blowing out.

Now maybe it will start to leak, and if noticed, it can be changed, but in the case above, he wasn't so lucky.

Does this point of failure give anyone else pause for concern? Or is it just me?

I mean, isn't this the way the story always goes??? Thousands invested and a lousy twenty dollar part put him in a ditch... or worst.

So any thoughts or experiences or pics of a spring loaded pedal switch install?
Click to expand...

The NOS one has the case crimped over the top to keep the plastic part in place. I'll try to get a pict.
 
Harley Switch and ACDelco fail

Both are designed the same... plastic switch plug inserted in housing, then a die presses the end over the edge of the switch.
 

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I've had countless hydraulic switches fail in recent years. I've been using GM style lever switches on the bottom of the toe board. Napa SL129 or BWD S191
 

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Automotive Stud said:
I've had countless hydraulic switches fail in recent years. I've been using GM style lever switches on the bottom of the toe board. Napa SL129 or BWD S191
Click to expand...

I have one as well & was racking my brain as to where it should be placed. Of course, I didn't have the floor in at the time. LOL!
 
Do your research on the dual-cylinder brake setup. They are difficult to install so that one half will work if the other half fails. There is normal not enough pedal travel for them to work. It can be done, but it is not just a bolt in.
 
Automotive Stud said:
I've had countless hydraulic switches fail in recent years. I've been using GM style lever switches on the bottom of the toe board. Napa SL129 or BWD S191
Click to expand...

These are great switches....THEY WORK! Simple as it gets. Here is a picture of the switch mounted to the Ford's wooden toe board, with the brake pedal resting against the spring-loaded arm. DD

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Why fool around with those crappy hydraulic switches when EVERY decent parts store has the mechanical switches that A.Stud and Coop are showing pictures of?
There is a right hand switch and a left hand switch.
Either one will work on most pedals tha pivot below the floor.
I have one on my F1, I have one on my ‘48 Nash Ambassador and one on my ‘29 Nash and one on my ‘26 Model T Ford.
I also have two new spare switches. They are STANDARD SLS40 and STANDARD SLS43.
One is going on An MGTD that I am restoring an updating.
I can not be bothered with hydraulic switches, sespecially since my cars have DOT5 fluid.
Having worked in a bid gas station in St.Paul I’ve seen a lot of cars come in on the hand brake because the switch blew out.
 
Before you finalize your choice of MC.....I used a BOSS 429 MC (15/16" bore) on my '40 coupe (disc fronts).......I had to "section" the cover to clear the floorboard.....also had to lengthen the push rod by the thickness of the MC adapter mount......otherwise a great piece. I am told the Corvette MC will fit without modifying it......something to consider....
 
There has to be a reason cars have not come new with a hydraulic stop light switch for several years. They’re not safe!
The old Chevy/GM switches are easy to mount and wire.
Just two small screws or bolts through the floor.
 
I've never had a issue with the new switches.... I did however have a NOS switch cause me to end up running a 39 Ford I had into a fence when it failed.
 
TFB said:
I was recently researching parts and came upon this negative product review for a hydraulic pressure switch for a brake system. It carries a very reputable name... ACDelco, but who knows if it's genuine or a knock off. Many parts are that way anymore.

Here's the part link
https://www.amazon.com/ACDelco-U855-Professional-Brake-Switch/dp/B0012OZO1I/?tag=atomicindus08-20

Since I'm in the process of overhauling a '39 setup on a '35, it got me thinking about this potentially weak link in the system. I know there's been countless discussions about single vs. dual systems, and the safety factor in redundancy. But this switch seems to me to be a big problem. They all seem to be made the same way, metal housing with a plastic insert that's then crimped over.

I've decided to try a '67 mustang MC setup which would be better if I used a pressure switch and had a failure I'd still have half a system, but I was wondering if anyone has used or knows of a conventional mechanical pedal switch setup that available? I don't know when Ford switched to that type switch but maybe that would be a better option. Thanks for any input.
Click to expand...

Hey. If you are worried about a blow out on a brake switch, go back to original mechanical brakes on your 35. Give us a break man. I've been in this hobby for over 50 years and have NEVER had a brake light switch "blow out" as you seem to be worried about. Fail to work electrically, yes. Leak a little, yes. BLOWOUT, never, and have never even heard of one blowing out.
 
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