Brake light question

[Russ Dickey]

My brake lights don't want to come on unless I am really standing on the brakes hard. Is there a way to either adjust the pedal or the switch which would make the switch more sensitive?

Thanks,

Russ

Unique 289FIA - Chassis #9229 - Viking Blue

[Jim Harding]

Russ,

I've heard that the brake pressure type switch can go bad and cause this condition. I'm guessing, but did the switch function normally at one time? Just might need a new switch.
With mine, I replaced that one with a mechanical switch that operates of the brake pedal..... the light comes on just before the brakes start to grab.

- Jim -

Jim Harding
La Plata, Maryland

1982 #3004
http://www.capitalareacobraclub.com/albums/album26/1aLeftside.thumb.jpg

[wlewis]

Russ,
Mine operates just like yours.
Walter

[weaver]

It sounds like your brake bias is adjusted more to the rear, how do your brakes feel?

Alan

[ralphscott]

If adjusting the bias does not do the trick go to NAPA and get a new brake pressure switch SL 134 Echilin That is what worked for me. Mike Fields thought I was one heck of a driver last year when we went through the Smokies on the breakfast run Fri Morn As I roared into the turns and from his perspective "never touched the brakes" He did not realize I was standing on em!!:D

Ralph

[Russ Dickey]

quote:Originally posted by weaver

It sounds like your brake bias is adjusted more to the rear, how do your brakes feel?

Alan


Alan:
I'm no grand prix driver, but I've had the chance to push the car fairly hard during some autocrosses this summer, so I'll do my best to explain. The car requires a lot of pedal pressure to slow down (which I thought was common), but stays straight under hard braking, and I haven't had the back brakes lock up before the front, so I thought the bias was ok.

Should I go do some panic stops this weekend to double check, and if so, what braking characteristics am a shooting for to know that I have it set correctly?

Thanks to all of you that have replied. As always, very helpful.

Russ

Unique 289FIA - Chassis #9229 - Viking Blue

[clayfoushee]

Over the years I've been here, most people have said the car works better with about 2/3 bias on the front (similar to what Alan said above). I changed mine accordingly a couple of years ago, and it worked better, including the brake lights.

Clay

'98 Unique #9299, 427FE side oiler (452.1-stroker), top-loader (close), 3.31 rear

Annapolis, MD

[Justin Upchurch]

Russ,
Alan was explaining the bias adjustment and light sensor to me at homecoming, apparantly the sensor is triggered by the front brakes. To tell if you need to crank in more front bias have someone follow behind you while you press on the brake. If you need more front bias the person following you will notice the car start to slow before the brake lights come on. After Alan told me what to look for I did notice that several cars at homecoming were in deed already under heavy braking before the brake lights came on.

Justin

[WYT VNM]

quote:Originally posted by ralphscott

If adjusting the bias does not do the trick go to NAPA and get a new brake pressure switch SL 134 Echilin That is what worked for me. Mike Fields thought I was one heck of a driver last year when we went through the Smokies on the breakfast run Fri Morn As I roared into the turns and from his perspective "never touched the brakes" He did not realize I was standing on em!!:D

Ralph


Pick this answer even if you get the bias right !

Dan Fowler, better known in Kit Car as Don Flowers. *427SC *428MSG with goodies *Tremec *3:31 posi *Ford Performance White w/light stripes *Grey interior *completed 1999

[Russ Dickey]

quote:Originally posted by clayfoushee

Over the years I've been here, most people have said the car works better with about 2/3 bias on the front (similar to what Alan said above). I changed mine accordingly a couple of years ago, and it worked better, including the brake lights.

Clay

'98 Unique #9299, 427FE side oiler (452.1-stroker), top-loader (close), 3.31 rear

Annapolis, MD


Clay:
How do I know when it's properly set at 2/3 to the front?

Russ

Unique 289FIA - Chassis #9229 - Viking Blue

[Mike Geddes]

Russ....here's what I've found ...for what it's worth.
The brake switch position as supplied from Unique is wrong.
My switch faces up from the little hydrulic junction block.
The capilary thru the threaded section of the switch never gets
filled with fluid when you bleed the brakes.
Air is very compressible compared to fluid...the pressure does not
always operate the contacts....Unless. as you have noted
"stand on it".
Change the angle of the switch if you can.....or get a new one
as suggested.....maybe those models require less ( air ) pressure to
operate.
Cheers.........Mike

Mike Geddes

[spd4me]

Best way to check brake bias is to take car out after rain when pavement is wet, get friend to stand on side of road, drive by and put on brakes hard and see which locks up first. Front or back.

[ralphscott]

I also put on a brake Bias remote adjustment to really get the feel for it Wildwood #340-4990 Precision Brake 1-866-992-7253. I like it and it is easier than crawling into the footbox every time you want to change the bias. It is the Blue knob with the red decal in the picture below -- look at the right hand side of the steering wheel and you can see the knob under the dash above the left hand side of the tranmission tunnel. Very easy to install and very clean and a very good device to easily experiment with bias.
http://www.uniquecobra.com/uploaded/ralphscott/DSCF0026.JPG

Ralph

[427sc]

Ron Francis at www.wire-works.com may have your answer. They sell a low pressure hydraulic brake switch under part number SW-32 I believe. They also have a variety of other types of brake switches if you want to convert to something else. When you get to the web site, just do a search under brake light switch. Cheers!

[pgermond]

I must be living right, because I haven't had a problem with the brake switch (yet). I also installed the remote bias adjuster that Ralph posted (money well spent). If the hydraulic switch does fail, I will install a mechanical switch in the footbox. spd4me - the old wet pavement test, huh? [8D] So, do you grab someone you aren't too fond of to stand out in the street to check which tires lock up first (should have suggested that to my X way back when)? ;)

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

[clayfoushee]

Russ, you can almost just eyeball it with the bias adjustment(threaded rod) on the pedal. It should be about 2/3's to the left. That is to say, about 2/3" of the rod's length should be on the left side of the pedal to approximate 2/3's front bias. That's how Alan told me several years ago to do it.

Test drive and re-adjust as necessary. I just did it once, and when I put the slightest pressure on the pedal I get brake lights, without electric switches or other tricks.

Clay

'98 Unique #9299, 427FE side oiler (452.1-stroker), top-loader (close), 3.31 rear

Annapolis, MD

[rdorman]

Get your bias right and recheck. My bias bar is set almost dead center because I changed components in order have the system naturally balanced.

To set bias. Set the bias centered to start, be sure the bar does not bind in the tube (push rod length needs adjusted). Find a large deserted lot where you will not attract undue (police) attention, take a helper. Have them stand by the braking zone. Get the car up to speed and apply brake pressure until the tires lock. Have your observer tell verify which locked first, front or rear. If front, turn towards the rear master cylinder about one or two turns at at time until the rears lock first, go back a turn or two and verify that the fronts lock before the rears. If rears, do the opposite except when the fronts are locking first, you are done. Close enough.

Wet pavement calls for more rearward bias so with this setting you will lock the fronts LONG before the rears. Better than the other way around.

Try again but this time in a large circle, make sure the rears don't lock first.

The switch, in my opinion, it should be facing upward, below the line and fitting. Air bubble. A low pressure switch (didn't know there was one! Thanks!) could do the trick, but a mechanical switch you know will work. Of course, if you adjust the height of the peddle then you would have to move the switch as well so keep that in mind.

If you car still takes to much effort to stop once the bias is right, send me an email and we can work through it. I used to carry a calendar with me to schedule my braking activity! Most of the problem was in the bias and pushrod adjustment.

Rick

http://www.ohiocobraclub.com
http://www.londoncobrashow.com

[Russ Dickey]

I have the remote bias adjuster dial mounted on the floor just in front of the drivers seat, so it's easy to adjust. I also live in a rural area with lots of open two-lane country roads - and have access to a large open parking lot at work, so I can start messing with it based on all your feedback.

You guys are awesome. Thanks for all the replies.

Russ

Unique 289FIA - Chassis #9229 - Viking Blue