Page 1 of 2 12 LastLast
Results 1 to 15 of 26

Thread: Hard/stiff brakes, but no brake or abs lights

  1. #1
    Join Date
    Jul 2010
    Posts
    13

    Hard/stiff brakes, but no brake or abs lights

    I recently purchased a 91 SC with a 5sp and was coming down the exit ramp yesterday and the brakes became very hard. There is no power assist. I've been reading a lot of threads and have noticed everyone saying that their brake and abs indicators have come on. Mine have not and in fact they don't even come on when i first start the car or pull up the e-brake. I can hear the pump motor but it's not very loud (not sure if it should be) and it never shuts off. Any ideas or suggestions? Thanks so much for your help.

  2. #2
    Join Date
    Oct 2004
    Location
    Charlotte, NC
    Posts
    8,159
    The ABS and brake lights may be burnt out or not even in the cluster....

    If your ABS motor is running all the time, it is either a bad relay that is stuck in the closed position or the pressure switch has failed.....

    It sounds like the pump motor is wearing out.....

  3. #3
    Join Date
    Nov 2010
    Location
    johnstown,pa
    Posts
    292
    I never had an abs motor go nuts so i cant say your symptoms fit the bill. Would it pulsate constantly if it were? Really stiff brakes and no stopping power, for me, has been 90% of the time a vacuum leak. Or a clogged vacuum line. I bought a car where the previous owner duct taped a line to repair it. When the tape got hot it slid and the line sucked shut. I've also had a power brake booster fail and it was the same. The diaphrams in the canister can leak and viola, hard pedal and no brakes.

  4. #4
    Join Date
    Jan 2010
    Location
    Bossier City, LA
    Posts
    2,290
    Quote Originally Posted by mmathews View Post
    I never had an abs motor go nuts so i cant say your symptoms fit the bill. Would it pulsate constantly if it were? Really stiff brakes and no stopping power, for me, has been 90% of the time a vacuum leak. Or a clogged vacuum line. I bought a car where the previous owner duct taped a line to repair it. When the tape got hot it slid and the line sucked shut. I've also had a power brake booster fail and it was the same. The diaphrams in the canister can leak and viola, hard pedal and no brakes.
    1991 ABS units ARE the power boost - no vacuum used.

    It's a rather strange duck.

    Google sometimes for "Teves Mk II Duffy" and read Duffy's tome on how it works, how it DOESN'T work, and how to fix it ...

    RwP

  5. #5
    Join Date
    Jul 2010
    Posts
    13
    Quote Originally Posted by the-big-e View Post
    The ABS and brake lights may be burnt out or not even in the cluster....

    If your ABS motor is running all the time, it is either a bad relay that is stuck in the closed position or the pressure switch has failed.....

    It sounds like the pump motor is wearing out.....
    Okay well I did the test that Duffy suggested where you ground the #4 pin on the connector to the pressure switch and the motor did not turn on. So its sounds like the relay then, right? where is this thing located? Thanks

  6. #6
    Join Date
    Jan 2010
    Location
    Bossier City, LA
    Posts
    2,290
    Quote Originally Posted by three51stang View Post
    Okay well I did the test that Duffy suggested where you ground the #4 pin on the connector to the pressure switch and the motor did not turn on. So its sounds like the relay then, right? where is this thing located? Thanks
    In Duffy's tome on the Teves Mk II brakes, he says where they are and which of the up to three is the ABS relay you're looking for (seems like Ford moved which one was which from one year to another ...)

    BUT - passenger side, on the firewall, there's up to three relays. One is brown if it's still factory (and if you buy the replacement, Advance Auto has both a black one that's like $12 and the brown one that's like $23 or something - go ahead and get the brown one, so in 2025 when you do this again, it'll STILL be "the brown relay"

    RwP

  7. #7
    Join Date
    Oct 2004
    Location
    Charlotte, NC
    Posts
    8,159
    Quote Originally Posted by RalphP View Post
    go ahead and get the brown one, so in 2025 when you do this again, it'll STILL be "the brown relay"

    RwP
    LOL.....

    Now that's funny.....

  8. #8
    Join Date
    Jul 2010
    Posts
    13
    I just read the article and found where the relays are located and.... There's supposed to be 3 and there's only 2(neither are brown)!!! and according to Duffy on 91 T-birds the far left one is the Hydraulic Pump Motor Relay. And guess what? that's the one that's missing. I can see the mount where it's supposed to be and its no where to be seen. Any ideas?
    Last edited by three51stang; 04-09-2011 at 05:36 PM.

  9. #9
    Join Date
    Jan 2010
    Location
    Bossier City, LA
    Posts
    2,290
    Quote Originally Posted by three51stang View Post
    I just read the article and found where the relays are located and.... There's supposed to be 3 and there's only 2(neither are brown)!!! and according to Duffy on 91 T-birds the far left one is the Hydraulic Pump Motor Relay. And guess what? that's the one that's missing. I can see the mount where it's supposed to be and its no where to be seen. Any ideas?
    Advanced Auto lists a BWD replacement for about $12 ...

    RwP

  10. #10
    Join Date
    Jul 2010
    Posts
    13
    Okay so I replaced one of the two relays and nothing. Then I took the new relay back out and put it in the other spot. Still no good. I'm not sure if it was okay to do that.
    The only other thing I could think of is that right after the brakes stopped working I added a bunch of brake fluid thinking it had just run low. It reads at the line now that says, "level with accumulator charged". This may be way to much considering the accumulator is probably not charged. I dunno... Just throwing out some ideas...

  11. #11
    Join Date
    Oct 2004
    Location
    Charlotte, NC
    Posts
    8,159
    You might have to dig down between the fender and the firewall....

    Sometimes the brown relay will get lodged down there....

    Have you checked for power at the pump motor connector located on the side of the master cylinder assembly....

  12. #12
    Join Date
    Jul 2010
    Posts
    13
    Quote Originally Posted by the-big-e View Post
    You might have to dig down between the fender and the firewall....

    Sometimes the brown relay will get lodged down there....

    Have you checked for power at the pump motor connector located on the side of the master cylinder assembly....

    Yeah I just looked again. Don't see it or feel it anywhere? Could it have came with only 2 relays?

    I'll check for power next. Thanks
    Last edited by three51stang; 04-10-2011 at 08:49 PM.

  13. #13
    Join Date
    Oct 2004
    Location
    Charlotte, NC
    Posts
    8,159
    There has to be a third relay somewhere in that area....

    Or at least a connector where a relay would go....

    The three relays are: WOT A.C. cutout relay, anti-lock power relay, and hydraulic pump motor relay.....

    The first and second relays are grey and the third is the infamous brown relay....

    There is a relay mounting tree attached to the firewall where all three relays are suppose to be secured....

    All three relays will be within 3 - 5 inches of that mounting tree....

    Use a flashlight, not a trouble light, to look down between the fender and fire wall....
    Last edited by the-big-e; 04-10-2011 at 11:59 PM. Reason: Research

  14. #14
    Join Date
    Jul 2010
    Posts
    13
    Quote Originally Posted by the-big-e View Post
    There has to be a third relay somewhere in that area....

    Or at least a connector where a relay would go....

    The three relays are: WOT A.C. cutout relay, anti-lock power relay, and hydraulic pump motor relay.....

    The first and second relays are grey and the third is the infamous brown relay....

    There is a relay mounting tree attached to the firewall where all three relays are suppose to be secured....

    All three relays will be within 3 - 5 inches of that mounting tree....

    Use a flashlight, not a trouble light, to look down between the fender and fire wall....
    Well I've looked a 3rd time and no luck. I've been very thorough. The mounting tree only had those two on it.

    Also there's one grey relay and one black, not two grey. But I've noticed that the Black relay is plugged into a brown connector plug. Could someone have already replaced the brown relay with a black one?

    Here's pics of the two relays.



  15. #15
    Join Date
    Oct 2004
    Location
    Charlotte, NC
    Posts
    8,159
    So far, all of the SCs that I've checked have three relays.....

    The first picture is the relay area for my 92 SC.....

    All three relays are circled in red....

    The second picture is an after market relay for the pump motor, it does have a brown retainer clip....

    The last picture is the same relay that you have a picture of.....

    I would think this is the anti-lock power relay....

    You can check for proper relay operation.....

    The relay will click when you add power to the two small terminals on the relay....
    Attached Images Attached Images    
    Last edited by the-big-e; 04-11-2011 at 04:07 PM.

Similar Threads

  1. Brake problems, no ABS, sometimes rock hard pedal
    By rev in forum Technical Forum
    Replies: 8
    Last Post: 10-14-2007, 05:39 PM
  2. Continued ABS woes (and others)
    By gregs90sc in forum Super Coupe Club of Ontario
    Replies: 22
    Last Post: 07-11-2007, 08:35 AM
  3. brake pedal/ lights
    By goodguy in forum Technical Forum
    Replies: 6
    Last Post: 06-09-2005, 10:40 AM
  4. No Brake lights or Interior lights
    By Sharkie in forum Technical Forum
    Replies: 3
    Last Post: 11-08-2003, 07:06 PM
  5. ABS / Brake Problem
    By 93scto in forum Technical Forum
    Replies: 11
    Last Post: 07-02-2002, 09:27 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •