WesDe

Ok guys. Recently had installed a set of 4.10s on mystang. I have done almost everything on the car myself, but I know nothing about rearends so I had it done at the shop. After i picked it up my ABS did not work.The guy told me that once I go bigger than stock, the speed sensors no longer read the accurate speed and that is why the ABS will not work. He said that there is no way of fixing this except back to stock. Is that true or is he pulling my leg. i don't really need it but I just want to know if this is true or not. by the way its a 94 5.0 with 4 wheel disc. Stock 8.8 rear.

roundman

methinks he is pulling your leg on this one. the wheel speed sensors use a pulse generator and a toothed wheel to count the revolutions of the wheels and then this signal goes to the computer for the ABS system which monitors the wheel speeds to determine when a wheel is locking up. changing your rear gears should not have affected these sensors unless they broke the pick-ups or the wiring from them to the ABS system. I'm not 100% positive about this, but I pretty damn sure this is correct. You might call the Ford Tech line at 586-468-1356 to verify that what I'm saying is correct before you go jump on the mechanics who installed your gears. you might want to also check for a blown fuse for the ABS system if it shows one in the owner's manual.
Let us know what you find out about this as I for one am interested in the answer too.

VertStangGT86

Well the gears aren't gonna change how many times the wheels have to turn to go the same speed so it shouldn't do anything on that end. It will change how many RPM's the engine will be at at certain speeds and it's possible the computer factors all that in. I don't see how it would really be a big deal though. I'd call either the ford tech line or call the mechanic back and ask him to explain why it doesn't work to you.

WesDe

Ok. Thanks for the info. Both of you guys were correct. The tech guy said that the ABS ahould not be affected by the change. He thinks that the shop damaged the sensors because they need to be removed in order to pull the axles out. He also stated that in most cases it is not an issue if they broke them or not. He said that even if they had taken them out correctly, upon re-installing a lot of the sensors will just not work again on an older vehicle. His advice was to check the wires and fuses which I already did and everything seems to be connected and no blown fuses. My question is do you guys know of a way to check if the sensors are still working(check resistance, etc.) these things run $120 a peace and they are not returnable because it is an electric part. If they are not working for sure then I will go ahead and change them. Also I hear noise from the front hub, i think it is time to change it. The new unit come with new speed sensor on it so I'm wondering if the front is causing the ABS not to work because it is bad. It might have just been a bad timing with the car being in the shop on that day. On the other hand the hub and sensor are separate pieces and even if the hub is bad, the sensors should still be good. Ford wants $75.00 to check what is wrong, and I don't want to spend the money just so they tell me something that I already know. Any suggestions now that we found out what is wrong. I don't feel like arguying with the shop because they did a good job on the gear and they did not charge me a lot for it.

VertStangGT86

Did you ask the tech guys about testing the sensors? Do you have a workshop manual you might be able to check? Mine only goes to 93 and I didn't see anything about ABS in the index.

WesDe

Yes I did, but they won't give me any info. He said "check with your local dealer". Anyways I have a Chilton's but it only explains removal and instalation. i guess i will just ride it without ABS, just don't feel the need to spend $200+ on sensors. maybe I will pick some up from a junk yard. I did ask around and nobody seems to know how to check ABS sensors. I did look at them today after work and they look OK. If you guys find something out please share it. Thanks again.

WesDe

Ok. I figured it out. One of the rear sensors was bent down and too close to the teeth on the ABS. I have heard that they have to be at least 1.6cm. away form the teeth. I did not know how much 1.6cm. was so I just took micrometer and measured the other side. After I bent it up a little the ABS light went off. Thanks for the tip guys. [sm=smiley20.gif]

roundman

anytime we can be of service don't hesitate to ask! LOL
as far as I know, the sensors are what's called pulse generators. they generate a magnetic field that is interrupted by the slots passing by in the gear like wheel, so the output voltage from them should be a discrete blip signal each time the slot passes by the sensor. don't know if this can be read with a volt meter, but it sure could be seen with an oscillascope, but I don't think too many people have one of these in their toolbox! LOL
glad you kept on troubleshooting it and found the problem, give yourself a round of applause![sm=smiley32.gif] lots of guys would have given up and taken it to a dealer and paid $75 for a few minutes of work and you didn't!

nhdungeonracer

WesDe, I would go back to that garage and give them my thoughts, especially since you actually FIXED their screw up!! If I'm paying for their "expertise", then they better get with the program.
Glad you did get it fixed though. Great to have guys like Roundman and VertStang (as well as others) here isn't it? [sm=smiley20.gif]

WesDe

Its definetly good to have these guys and their exprert opinions on some of these problems. Sometimes we get problems that we can't figure out and it is always nice to have someone to help you out when in need. i have figured out a lot of things on my own just by trial an error, but it is always nice to have someone to point you to the right direction. Once again thanks to all of you for your help and I will definetly try try to help out as much as I can. The car runs good now so I will have more time to help out as well.[sm=smiley20.gif]