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Pulsing brake pedal after bearing replacement


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Billnoy
New User

Jul 29, 2018, 8:42 PM

Post #1 of 9 (492 views)
Pulsing brake pedal after bearing replacement Sign In

 1997 Toyota T100 4x4 ,3.4, auto, 170K
No problems with brakes until I replaced the front wheel bearings ( all 4). Used the recommended preload on the bearings but now have a pulsing pedal especially at highway speeds. I did'nt check the rotors for runout because there were no problems. They looked fine . Pad wear was even. No pulling before or after bearing replacement.
Ideas anyone ?


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jul 30, 2018, 1:50 AM

Post #2 of 9 (485 views)
Re: Pulsing brake pedal after bearing replacement Sign In

OK - Just looked for how this still has (4) as you said and apparently they did use inner and outer packable bearings and races on this. First question is what went wrong that you needed all of them? I don't go for that in general depending on the situation.


Do these look like this type? >

See they sell the bearing and the race separately or a mistake in exactly what you have? If you don't do races matched with the bearing there's simply no point IMO. You do have to set that race and know it has in fact perfectly hit its stops and really should be a matched set with the bearing not this garbage. Anything gone wrong rotor will not run true you said you didn't check for runout on them - right? Should have and also for this type check free-play essentially zero but right at that not more and not less before locking it there.


Grease on rotor will cause the pulsing if not cleaned off if you got those all dirty.
Caliper and pads must go back to where they were if fine and even as you said. Any rust ring on outside of rotor can and will chip off in one area if not removed totally which about means do the front brakes as well if like that - the whole job.


There's a lot of places to screw up this job. Others may disagree for their reasons but you can see the "galling" on a race of which bearing(s) are bad and which ones are good with this type is hard to see always wrecks both race and that bearing as a matched set.


Quality of this stuff really lacks also.


Miles up there (it is at 170K) on them I ask why all 4 sets are bad. The common reason would be they were submerged in water all grease in there would turn to a milky yuk as evidence.


4X4 or not the brakes and bearings were not meant to be submerged ever if so can take a few months and all this stuff fails not right away and more will go wrong over time with brakes,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jul 30, 2018, 4:47 AM

Post #3 of 9 (479 views)
Re: Pulsing brake pedal after bearing replacement Sign In

As Tom pointed out. It sounds like the races are not fully seated.

That will destroy your new bearings really fast.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Jul 30, 2018, 6:07 AM

Post #4 of 9 (474 views)
Re: Pulsing brake pedal after bearing replacement Sign In

Ayup! OP - this was the way virtually all bearings were done since the Flintstones is actually late now except for trailers. YOU TOTALLY NEED TO KNOW AND SEE THE FAILURE AND CAN. The sound of a race being properly bottomed into where it goes is unique a different tone that it is.


I'm totally shocked they'll sell just the bearing without the race is pointless the ruin each other if bad. Ruined doesn't look that bad at first I'll let you Google out what bearing "galling" looks like you can see it if wiped clean before a bearing is going to fail unknown how long you have.
Do them all? Yes for boat trailers submerged in water that are NOT sealed tight you can get whole hubs ready to go also fit assorted trailer things.


Hey - old phart here this is what everything was about gone from automotives to remove any need for actually being shown in person how to tell good from wrong ways to deal with these worked fine for 100 years.
Also because this sure will effect brakes if you don't catch this right away - a test drive you'll need not only what you did but brake work you weren't counting on.


So simple yet takes the right touch or it comes out wrong. Quality as I said stinks with this now avoid anything made in China if a choice. Have to add China could make anything or quality it wants to just are more willing to put up with a high failure rate and it sells better over price! Not worth it,


T



Billnoy
New User

Jul 30, 2018, 8:25 PM

Post #5 of 9 (455 views)
Re: Pulsing brake pedal after bearing replacement Sign In

 Tom, thanks for the reply and the ideas. I may have misled you just a bit about the bearings. All the inners and outers ( bearings and races as sets ) were replaced at the same time ( with Timkens from Napa). As soon as I experienced the pulse at speed I rechecked the torque sequence to confirm that the races were seated and found no problem there. I did not check the runout with a dial because I had no pulsing of the peddle before the bearing change.
Used brake clean,etc. I think I'll pull the wheels and check for runout.


Billnoy
New User

Jul 30, 2018, 9:01 PM

Post #6 of 9 (452 views)
Re: Pulsing brake pedal after bearing replacement Sign In

 Ok, I had to know so I pulled the front wheels and checked for runout,..........None.
So, maybe I messed up by putting fresh organic pads on it and didnt scuff up the rotors.
I've done it before without a problem but every day is a new day.

Any further thoughts ?


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jul 30, 2018, 11:06 PM

Post #7 of 9 (450 views)
Re: Pulsing brake pedal after bearing replacement Sign In

OK, Back some: Why the bearings in the first place? Timken is a great bet by name now need to know how thick rotors are and what condition? Just tossing in pads is AYOR all the time still stay with OE types more common to call for semi-metallic which is harder on rotors are marked with min thickness is almost never enough to turn them/machine just maybe once if some issue right away new.


Thin will warp lots easier even when they look fine adding new pads now changes the scene.
It's a '97 and still around so something is going right with this truck. What condition are the rotors? I mentioned rust on outer edge can make a ring/ridge and some comes off just pulling a caliper off brakes can then do the pulsing thing if you were just checking them not the work and new pads any type don't usually touch same exact area as the old ones and voila - there's your pulsing brakes.


What do you want to do now? You know it should have had new rotors if you did the pads they can be strong and safe but now not smooth as you'd like at higher speeds is probably asking too much for this partial job we haven't mentioned anything done to calipers, hardware also need re-lubing, checking if you are there just because.


Trying to see this whole truck and scene - it this just a truck to work with or altered with tires, wheels or other things for Off-Road use or just what do you have here?


Just me - a truck is either dedicated to work or a fun thing by now. Which is this?


Tom



Billnoy
New User

Jul 31, 2018, 6:28 AM

Post #8 of 9 (433 views)
Re: Pulsing brake pedal after bearing replacement Sign In

Thanks again Tom, I replaced all the bearings because a spin of the d side without the caliper gave off a little noise.
So maybe the Semi-Metallic pads would bite the rotors better that the organics and bed in ? Or maybe just pull them off and clean them up with some abrasive of some sort ?
The calipers measured at nearly full thickness and no runout, and the calipers are clean free and dry ( rust is not an issue here).
The truck is stock to the bone and used as a daily driver.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jul 31, 2018, 7:29 AM

Post #9 of 9 (427 views)
Re: Pulsing brake pedal after bearing replacement Sign In

OK - We are getting there I think? Organic pads to me means and could be specified (that's your job) throw more of the heat of friction at the rotor and semi-metallic tend to put it back to caliper and pads. Organics at least for a clunker just to get some real mess of a legal vehicle thru a New England Winter before junking it did break in fast even before given back to a customer who understood it was NOT the right job the car was doomed or would be soon.
You did what a lot of people do is replace ALL bearings and didn't find probably just which one was the culprit. That's a point for techs to disagree on. I've owed untold 100s of cars just the few I liked kept know those best and wailed miles on some never did a wheel bearing from known new vehicles! Take care of them - yes.
To me a bearing is bad new and unknown how long it takes to start showing up even this late! Usually it's water or some other whacked reason.
In short I don't know if there's a known bearing life for this type? Owned (you know your own best) many boat trailers and boats some required dunking whole trailer under water was a bitch to keep bearing good and salt water at that some or most of the time. Have seen all 4 so bad just dump the entire hub bearings and all or grease them right away they make "Bearing Buddies" for that.
Not the point right now. I think your rotors are warping and when checked are showing good. There isn't 2 mm's of extra metal on almost anything even this age stinks.
Heat? Just anyone should see a frying pan not set level cooking you get the idea then it's fine again when cool. Same game in a way.
It's bugging you or you wouldn't be here I guess this is what I know, fixed or not depending on budgets and never done to not legal unless a yard vehicle not to see public roads again.
As you did once you've driven at all bearing and seals rotors should spin free and silent is telling right away. I've seen some not be good in two weeks too new!
Said if good they about last forever and if not you don't know. Rotors are more known - they don't get thicker with use and warp if only when warm/hot then quit it.
Some you can see where they get hot already now a different color than the rest harder to see inside of course that's it NG nothing is going to fix that the metal has changed and harder or softer in spots. That's a reason rotors get tossed anytime pads are done.
One more: Used to work a new car dealer not long but many new vehicles had a paper wrapper around sun visor said go easy on brakes (whole new vehicle!) for at least 200 miles to allow brakes to "break" in! It was true and still is IMO.
For now the end reason is organic pads and rotors have been too hot the game is over all that must go for the cure.


2nd time one more: Live somewhat near Mt. Washington, NH has an autoroute to drive up and have also done Pike's Peak, Colorado. OMG breaks are glowing hot melt tires, wheel trim and smell like all hell never behave if not super careful on just those new or old vehicles any types.
So that's my call unfortunately if it's bugging you enough the solution is toss those things and assertively let new break in but good grief if a panic stop happens it's only $$ again use them!


Good luck it's your call now,


Tom







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