88' 911 brake light question

88'3xBlk911Cab · 03-02-2005, 02:24 PM

Are the brake lights hooked up to a peddle pressure sensor? I have noticed that my brake lights do not come on unless I apply moderate to heavy peddle pressure. I was following my husband and he came up to a light on a hill and only applied light pressure to stop.....no brake lights at all. I called him on his cell and said "there are no brake lights on the 911".....we then tested it off an on all the way home on the country road. Lights only came on if he applied a lot of peddle pressure.

Can this be easily addressed? I really don't want my baby getting rear ended. I am the type of driver that downshifts to slow a car and like to use light brake pressure so I know my lights need to be fixed. Thanks in advance for any advice/help.

Mary

RANDY P · RANDY P's Garage

Replace the brake light switches in the M/C. Two of 'em and it's a common failure.

Bill Verburg · Bill Verburg's Garage

Once again asearch would be informative
brake and light and switches

kqw · 03-02-2005, 04:40 PM

Quote:

Originally posted by RANDY P
Replace the brake light switches in the M/C. Two of 'em and it's a common failure.

Easily fixed.....

masraum · 03-02-2005, 05:42 PM

The brake light switchs (there's 2) in an '88 have nothing to do with the pedal. THey are in the master cylinder, and yes they are pressure sensors. They are cheap and a bit of a pain to replace, but not because it's complicated, just because the fluid can/will leak out when you switch them, so you'll want to be quick, and you need to bleed the brakes after changing them.

88'3xBlk911Cab · 03-02-2005, 06:29 PM

Thank you Randy, KQW & Steve. I will order the switches from Pelican right now.

Mary

88'3xBlk911Cab · 03-02-2005, 06:38 PM

Bill, thanks for the advice on the search. I should have done this before posting but I was at work, really busy and just threw a quick question up.

Por_sha911 · Por_sha911's Garage

Have someone press lightly on the brake pedal when you take the old sensors out. This will prevent brake fluid from leaking out. Be careful not to get brake fluid on your paint (nasty stuff). Do a complete flush since you have to bleed the brakes anyway. Also flush out your clutch. One Liter will do it.

88'3xBlk911Cab · 03-02-2005, 07:30 PM

Great advice Joe thx! I help with brake bleeding on our race car all the time so this should be a snap. We will do the clutch too as the PO never did DIY repairs and with 178K on the odometer I am sure it would be a good thing to do

Wil Ferch · 03-03-2005, 04:10 AM

Joe says..."Have someone press lightly on the brake pedal when you take the old sensors out..."

Good advice...for clarity...."press AND HOLD.."...like using a stick propped against the seat, to constantly depress the brake pedal while doing this.....

Wil

aj88cab · aj88cab's Garage

FYI.....Here is a "special fully adjustable custom tool" that I use to depress my brake pedal when working on the brake system......

Good Luck
Andrew

KFC911 · 03-03-2005, 06:02 AM

Quote:

Originally posted by 88'3xBlk911Cab
.... I am the type of driver that downshifts to slow a car ...Mary

Just a couple of comments...you obviously know your way around cars, but brake pads are a heck of a lot cheaper than the wear you're putting on your tranny imo. Also, if you don't have one, you should get a pressure bleeder. While there are numereous ways to bleed your brakes, the pressure bleeder is the only way to bleed your hydraulic clutch (which will also be required after opening the system)...might as well 'kill two birds' while you're at it.

rick-l · 03-03-2005, 10:09 AM

Quote:

Originally posted by KC911
the pressure bleeder is the only way to bleed your hydraulic clutch (which will also be required after opening the system)...might as well 'kill two birds' while you're at it.

Why would she need to bleed the clutch. I don't think she will empty the resevoir unscrewing /screwing the sensor.

Clutch tranny wear from downshifting? Have heard that before, Yes it is wear but is it significant?

KFC911 · 03-03-2005, 10:32 AM

Hmm....Rick, you may be correct re the 'clutch bleeding' after simply replacing the sensors... If I'm incorrect, I now stand corrected...thank you! As far as using the tranny to slow the car...I've always been told: use the brakes for what they are designed for, and likewise for the tranny. How much wear...??? I don't know, but brake pads are cheap compared to ANY unnecessary 'wear & tear' on a 911 tranny imo.

88'3xBlk911Cab · 03-03-2005, 11:02 AM

I don't use the downshifting to always slow the car and I do agree this moves the wear from the pads to the clutch/tranny. I do downshift getting off the freeway etc, from 5th to lower gears but never below 3rd. And I only do this if the ramp is really long and think this is better than lugging the motor in 5th until I need the brakes. At short stopping distances I only use the brakes.

Thanks again for all the help on this thread!

Por_sha911 · Por_sha911's Garage

I said to FLUSH the clutch. You will find that some of the nastiest fluid comes out of there because most folks only bleed and/or flush the brakes and the fluid in the clutch is OLD. I believe its factory PM. You can do the clutch with a vacuum bleeder but its a lot more work than a pressure bleeder like the Motive.