Got in my truck yesterday to leave to go see JerrySeinfeldhttp://www.dieselplace.com/forum/smileys/Clap.gif. I started it up went to put it in gear and my brake felt fine but seemed different. Put it in gear and i had no stopping power....There was pedal and everything there it jsut didnt stop...Then it started to stop but the pedal was pulsating like ABS was kickin in...WTF I continue to go back and forth in the dirveway and seems to get better...Still pusaliting for liike the first sec i touch the brake, but otherwise fine. I took off and the brakes were fine forthe next 40 miles. Only puslated like 2 or 3 times after doing it first thing....
I called a friend, who had a problem similar and his ended up being this speed sensor??? I guess they get rusty and then dont since the wheel speed at first, thus causing it to kick ABS at first...It might be possible as i havent driven the truck since Sun. Noon and theres been some good dews here in the mornings...I stopped at a chevy dealer on my way (Spurr in brockport for the locals) and they stated it sure sounded similar to that, but no way to tell unless you tear it all apart. Said it could just be a sensor, or might have to replace the whole hub.

I asked them if it owuld throw a code, but they said ti was unlikel, and nothing came up in the little info thing, nor did any ABS lights or anything come up....Brakes were fine rest of the trip up and back...
Any ideas???http://www.dieselplace.com/forum/smileys/Confused.gif
Thanks-Adam

It could be sensor or you could be on the raggedy edge of programing as I see you are running oversized tires and some truck can be very fussy about that with ABS as it gather drive shaft speed info and wheel speed info and if the do not "match" the ABS kicks in. You could be right on the edge so to speak and it takes very little to set it off. Make sure ECM is properly programed for current tire size.

Polarbear,


I had a problem were my truck sat for a couple of weeks and when I started I had all kinds of lights come on.


I climbed under it and found out some critter made his home on the transfer case and chewed the wires up that went to my speed sensor. The wires I am speaking of are the driver side of the drive train.


Might want to take a look under there.


Good luck, Allie

Snoman-It could be that, but ive ha dthe truck since may 1 w/the tires and having had any problems til now...I know the computer is programed to 265 tires, thats as far as the dealers tech 2 went...maybe i should try and find one to go to 285...
Allie-I dont think(hope) i have any critters, sinze it seemed to work alright after the first couple mins. But im going to definitly give it a look tonight...
Thanks for the tips guys-Adamhttp://www.dieselplace.com/forum/smileys/Clap.gif

It is just a thought, it could still be a sensor problem but given the problems I have "seen" with GM ABS and tire size and /or axle ratio changes I felt that the programing isssue was worth reviewing anyway.

...I know the computer is programed to 265 tires, thats as far as the dealers tech 2 went


Thanks for the tips guys-Adamhttp://www.dieselplace.com/forum/smileys/Clap.gif


OK, tell me more about this! I thought the tire sizes could not be changed in the ECM by the dealer. At least that they wouldn't!

Crazy- My truck came w/the 285's dealer installed. I asked them if they had done anything to adjust for rotation raito. They said they bumped it up to 265... they said they couldnt go up any higher tho. Sorry, but i cant positively remember if it was that their tech 2 didnt have the range, of it the compute(ECM i guess you call it) wont let you adjust more than 265....

Did you find out anything about your abs Polarbear? I seem to be having some sort of abs problem on my 01 2500hd 8.1 with 70,000 k. The abs kicks on when moving slow and you apply brakes. Seems to happen more frequently when turning. I have a set of very worn 245 revos, does anyone know if that could make the abs want to kick on?


If one of the wheel speed sensors is bad how could you tell which one? No warning or check lights come on. Hope it just needs new rubber. 265's next time.

Cheddy- I stopped at my dealer(Hartway) last thrus or fri and they said its possible that when i went to shift out of drive and stuff that it could be the speed sensor. He also when on to say that the sensor will only act up and about 5mph, 10 tops....anything higher and youve got another problem. When we discuss the vibration i sometimes feel when i put my foot on the pedal at highway speed, he said thats prolly from the rotor contacting something?? the pads maybe, i dont know im not particulary brake savy so....They like Spurr, said that it may throw a code, but not likey. Most likely would have to take it apart and look at them, but it seems like i remember something about they could test them to...
Sorry cant be of more help, but thats all ive discovered so far. Havent had any problems since that one time neither...http://www.dieselplace.com/forum/smileys/Confused.gif
Where in WNY are you?

Polarbear, I live in Wyoming about an hour south of Albion. Did they say if the driveshaft sensor is prone to fail or is it the individual wheel sensors? I wonder if all of our roadsalt tends to rust the wheel sensors more than normal. I have allready replaced front and rear rotors because of severe corrosion.


On a related subject I have noticed when going through real deep snow banks and its packed in the wheels My truck will throw the check brake light and the abs comes on real easy. I always figured the snow interfered with a wheel sensor and thats what triggered the light as it always went out after a couple miles on the road.

They never mentioned anything about a driveshaft sensor...the way it came across to me was that it was individual sensors...however if i was going to do one, i think id like to at least check or look at the other one....
Im pretty familar w/Wyoming county. Down that way sometimes getting parts or whatever from Lamb & Webster...I was down your way on sunday at the grass drags in Marilla. hoping to come down that way this winter a bit to do some snowmobiling...http://www.dieselplace.com/forum/smileys/smiley20.gif

look for metal shavings on the wheel speed sensors, as for the bigger tires giving problems, I've got over 25000 miles with 315's with no problems. The abs, ecm, trans etc. has no idea what size tires you have. Sometimes surface rust on the rotors can give you a "grabby"brake and can induce ABS functions, also most HD's have hydro boost which works off the power steering pump, sometimes in slow speed turns the steering box uses most available boost from the pump leaving little left for the brakes. Follow the hoses and the steering box gets first dibs on the flow from the pump. Hopes this helps. Rick

reread your post about dew. Here in Fl rotors can develop surface rust in just a few hours, just ease on brakes while going slow and rust should go away, just be careful not to smoke brakes