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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Stop light switch

Where can I find a good quality hydraulic switch?
My original looking (made in england) switch was getting unreliable, sticking "on", so I replaced it with one from LBCARCO. When installing it I noticed that the tapered fine thread nipple was a little loose and neededmore teflon tape than usual. I tested for leakage by pressing hard, then harder on the brake pedal. Boom! my foot went all the way to the floor. No brakes! The switch had failed. The bakelite part had just pushed out of the metal case (see photo)
The brand name on the box was uroparts.com. I e-mailed jeff at LBCARCO and warned him of the quality of this part. He got back to me right away and said they had no problems with these switches, and he sent me another one.
If the new one is the same design from the same co I won't use it on my car. Just comparing it to the original you can see how the new one would fail. There is just not enough metal rolled over to hold the bakelite in place.
Does anyone know of another source for these switches? I presume this came through Moss.
I believe the nipple is 3/16 pipe thread is this compatible with SAE? I have a chart somewhere but can't seem to find it today!
Thanks
Chuck
OOps my file is too big!
cj schmit

Off the shelf from NAPA Part # SL 144 . shown on the left. One on the right is a replacement from Moss a few years back


L E D LaVerne

Another shot.


L E D LaVerne

I do not find 3/16 as a size in either BSP or NPT.
Nominsl sizes for both are:
1/16, 1/8, and 1/4"

The BSPT Has threads of 28, 28, and 19 TPI.

The NPT has nominal threads of 27, 27, and 18.

NPT major diameters are; 0.2875, 0.300, 0.5025. (Tapered threads, these are nominal diameters)

BSP Major diameters are; 0.304, 0.383, 0.518.

In addition there are two forms of BSP a tapered thread and a straight thread.
I dont think you could use an "American" fitting without some effort.

Why not give Abingdon a call a see where they get theirs.

Jim B.
JA Benjamin

I own four vintage British cars and over the years had no end of trouble with the garden variety of cheap stop lamp switches supplied by NAPA or Moss. Mostly they would simply fail and refuse to turn on the stop lamps. Finally splurged and got the Ron Francis Wiring low pressure switch SW-32 and have had no more issues. As an added benefit these are a low pressure switch and thus activate the stop lamps at just a slight push of the brake pedal. They screw right into the T fitting with no problem. Further info at
http://www.ronfrancis.com/products.asp?dept=28

John Quilter
Eugene, Oregon
John Quilter (TD8986)

Chuck,
I got my replacement stop light switch from NAPA part number SL147SB. They took the number off of my original switch, which I think was Lucas, and said they could have one for me that afternoon for $11.09. I installed it that day, 7-5-2010, and it has worked just fine since.

Regards,

Bobby L.
B. F. Loughridge

Good to know John. I don't have any issues on the one on my TF.. It may be an old Lucas. The one on the TD how ever takes a whole lotta foot pressure before it makes contact. Might be a NAPA. Been meaning to change it out because it's only good for a panic stop warning.
L E D LaVerne

Here's what Ron Francis says: "A high quality switch with a much longer life than previous models available anywhere. Fits most cars, with 20-50 pounds pressure required, instead of stock units that need 60-120 pounds pressure to come on. Standard 1/8 inch Pipe Thread (9/16-18). ATTENTION: THIS updated version of this trusty switch is D.O.T. compliant which includes silicone fluid compatibility and it is capable of 200 -300% more cycles"

The switch looks like it would fit but is 1/8 inch pipe Thread going to be compatible with the T-connector in the TD? The clip-on wire fitting on the RF switch looks good because it might allow easy wire connection after the switch is firmly installed instead of winding up the wires and trying to install it wired.
Jud
J K Chapin

The stop light switch, regardless of the car it is use in is 1/8 NTP. Quite frankly the switches sold by Moss or at NAPA are junk! Even if they don't fall apart, they fail in a very short period of time. The only fix for this is either the Ron Francis (SW-32) http://www.ronfrancis.com/ or make up or purchase and install a relay/arc suppression circuit. See the article, Brake Light Relay in the Other Tech Articles section of my Homepage at: http://homepages.donobi.net/sufuelpumps/ Cheers - Dave
David DuBois

If it's 1/8 npt, Cole Hersee has very reliable switches. I have used their products for years on cars, trucks, heavy equipment and boats.

I will post a link later.

Jim
J E Carroll

As usual, Dave is "Spot on",, after having to replace a few fro, Moss and ABS, I got one from ron Francis,,many miles since, and it still works fine!!

SPW
STEVE WINCZE

Link to Cole Hersee:

http://www.colehersee.com/home/catalogs/

Stoplamp switches.
J E Carroll

Couple of thoughts - none of the connector lugs match either the grub screw type or the spade lug type used on our cars. Switch P/N 8626 has connector lugs that will accommodate small ring style wire terminals (I have one of these switches somewhere in my stash). Switch P/N 8638 looks exactly the same as the Ron Francis switch (it also has a Minimum order quantity may apply statement in the catalog). It would be interesting to hear back in a year or so from anyone using any of these switches.

Another question - can these switches be purchased directly from Cole Hersee by an individual, or does one have to find a vendor that carries them by the various P/Ns listed on the catalog pages? Cheers - Dave
David DuBois

Hi Dave,

You can purchase Cole-Hersee products at suppliers who deal in commercial trucks. I happen to have a sister who works for a large distributor who has been my source.

Having said that, it seems that there are fewer choices in today's online catalog than I remember in the master catalog I have at home. There's little demand for this type of switch in today's cars so perhaps they've just let them go obsolete.

Perhaps using one of the solenoids or relays as some have suggested is the way to go. I used one of the sealed marine type on my plow truck as the backup switch couldn't handle all the additional flood lights.

When I get off this trip I'll have a look at the olde catalog.

Jim
J E Carroll

Jim - Looking at the switches, they look the same as the Echlin switches and for the one with the packard connections, like the one from Ron Francis. I strongly suspect that there are only one or two manufactures of these switches and are wholesale out to a multitude of distributors. I have only used the switches Moss and NAPA (plus one new old stock Lucas). I know that the ones from NAPA are made by Echlin and I suspect that the ones Moss sell are too. I really wish there was a way to find out where the switches sold under different brand names were made. Barney Gaylord (MGA Guru) has a very extensive list of brake light switches by brand name and I know that all those places don't make their own switches.

Cole-Hersee web site shows one mechanical brake light switch like the after market Lucas switch used on the later MGBs. When I had such a terrible time with brake lights switches (first on the TD, then on the MGB), I decided to try the mechanical switch on the pedal box of the MGB. The one I got from Moss was made by Cutler-Hammer (a trusted name). That was the one that lasted a full two weeks! I finally managed to source a new old stock Lucas switch and also installed my relay/arc suppression circuit.

I have even seen at least one report of a Ron Francis switch failing in a bit over a year. I have started to wonder if perhaps the present day 1157 and 1156 light bulbs have more inductance than bulbs in the past, thus developing more of a voltage spike when the switch opens. I keep telling myself that this can't be the case - but I keep wondering just the same. Cheers - Dave

David DuBois

Problem could be the source of manufacture David. NAPA used to pride itself on the fact that the Echlin was made in the good old USA. Now sadly made in China along with just about everything else they carry. Hade to get a heater servo motor for my truck not long ago. Funny that the counter man stated I had a good part because in was made in Korea. Who would have thunk.
L E D LaVerne

LaVerne - I can remember when 'Made in Japan' was synonymous with junk. Now it is synonymous with high quality. South Korea is right on their heals. Cheers - Dave
David DuBois

I'm installing a relay in my system using Daves wiring diagram. I have some new relays and plugs used on GM products, so I'm assuming their right for the task. PJ
Paul sr

Chuck:

Are you sure that the switch is the problem?

If it is "sticking on" it is possible that your master cylinder is building pressure.

Been there, done that.

Mark Sherman
mrkshrmn at hotmail.com
Mark A. Sherman

Mark - 'Sticking on" is not the normal failure mode with the brake light switches on the MGs (that's not to say it never happens). The normal failure mode is for the brake pedal having to be pressed harder and harder for the lights to turn on, eventually requiring nearly standing on the pedal to get the brake lights on.

" I have some new relays and plugs used on GM products, so I'm assuming their right for the task."

Paul - Nothing special needs to be used, any relay that has at least one set of contacts that are normally open will work. Cheers - Dave
David DuBois

Chuck,
try slacking a bleed nipple if the brake light goes out you have a sticking master cylinder,it may loosen off with use.
Ray TF2884
Ray Lee

The original made in england switch was sticking ON.
Putting on the new switch solved that problem but when I stood on the pedal to test for leaks the guts came out of the switch and the pedal went to the floor. I cleaned the gunky fluid out of the original switch and put it back on and it works fine again. Jeff at LBCARCO sent me another uropart switch but it looks like the bakelite is in crooked and the rolled metal is lopsided. I don't want to take a chance on another one blowing out. Lots of real technical terms here, huh? This thing acts like the pressure relief valve on my moms old pressure cooker!
I'll see what NAPA has manjana..(sp)

Chuck
cj schmit

Chuck - NAPA has switches for the TD but unless there has been a sea change in the quality, it will fail in a very short period of time (interesting that the one from Moss is from Inter Motor - and outfit that has been singularly unimpressive). You have a couple of choices, go with the NAPA switch made by Echlin in China and install a relay/arc suppressor as I stated in my earlier post, or go with the Ron Francis SW-32 switch, which has had good reviews. Cheers - Dave
David DuBois

Might not be on subject here, but, I installed LED rear lights partly because they draw very little current. Thought this would extend the life of the Moss switch I installed.
But you have to be very careful you have good ground connection!
Peter Dahlquist

When my switch failed last summer I when through the same process to find a reliable replacement. I checked with one manufacturer, InterMotor, the current rating of their product, they told me that it was 8 amps.
For our usage we require 3.5 amps (2 21w bulbs at 12 volts) With a derating of 75% for a resistive load (filament lamps) this gives 6 amps In that case they should have a long life.
I finally bought an original Lucas one on fleebay.
John
J Scragg

This thread was discussed between 12/03/2013 and 19/03/2013

MG TD TF 1500 index

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