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2012 Odyssey, random brake pulsing

Pony_Driver

Red Skull Member
Joined
May 25, 2020
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1362
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2,173
not my vehicle, I don't have daily access to it.

A few weeks ago I replaced the DS axle and ABS sensor. Now, at speeds above 40 mph there is a random pulsing in the brake pedal. It is not present at slower speeds, even when you stomp on the brakes. Moderate braking seems to result in more of a shimmy and pulsation than 40mph to 10mph under hard braking. After a shakedown drive I went through a dozen or so stops from 20mph to zero and 40+ mph to near zero mph. The total miles travelled were 3, maybe 4. When I got back the DR front brake smelled hotter than the rest.
There are no DTCs and no ABS codes. What could be the root cause of this? It is not warped rotors. It seems odd that it is speed dependent and also odd that only one wheel seems affected. The pulsation seemed to start after the CV axle replacement.
 
that era is well known for warping rotors really often, but it's probably something unnatural since you just had it apart

did you grind the rust outta the caliper bracket behind the stainless shims? I use a cutoff wheel to do that
also gotta clean up any rust edging in on the slide pins, usually the lower ones start rusting first, use silicone grease and be sure to get it on the two areas the boot seals against the pin and the bracket

did you twist the brake hose around wrong when installing the caliper? that'll do it for sure

if you had the rotor off the hub and didn't get it back on in the exact same place on the hub it'll stack up the rust buildup wrong and cause runout, but that won't cause a hot brake like you describe
 
My wife’s 4Runner would pulse the brakes or shimmy the wheel but only at higher speeds and only sometime. New rotors/pads fixed that issue.
 
I lubed the slide pins, and wire brushed under the stainless pad slides. I didn't do the brakes, but the hose was twisted, not kinked. I reinstalled it correctly without the extra twist. I'm pretty sure the rotor went back on flat, but it could be the issue.

If pulling the ABS sensor fixes it, what's the next step? Another new ABS sensor? The new one isn't throwing a code.

Edited for spelling. :homer:
 
Pony_Driver said:
If pulling the ABS sensor fixes it, what's the next step? Another new ABS sensor? The new one isn't throwing a code.
Click to expand...
look at the trace.
You may have to gap the sensor
 
Bebop said:
look at the trace.
You may have to gap the sensor
Click to expand...
I'll look at it. It seemed like a plug and play deal since it fits into a hole and bolts into the spindle. Maybe a shim under the mounting lug? The old design was utter garbage and I had to drill out the old sensor. It was rust jacked into place something fierce, which was apparently a problem for them. Even in the earlier generations they had problems.
 
I had a customer's 1990 Porsche 944S4 with a bad sensor, was flat eating pads on that one corner. No codes, we replaced almost all of the hard parts, finally put the o-scope on the sensor and spun the wheel. Patern wasn't a nice sine wave like you'd expect, was 100% garbage. Computer thought that wheel was sliding and worked the hell out of the abs. New sensor fixed it.

Just remember, if it's new, that just means it's untested. SCOPE IT!!! :flipoff2:
 
Pony_Driver said:
I'll look at it. It seemed like a plug and play deal since it fits into a hole and bolts into the spindle. Maybe a shim under the mounting lug? The old design was utter garbage and I had to drill out the old sensor. It was rust jacked into place something fierce, which was apparently a problem for them. Even in the earlier generations they had problems.
Click to expand...
Super common on rusted out shit that the tone ring is also a big crusty and the gap is too important.
You need to look at the trace with a scan tool.

4x4mechanic said:
I had a customer's 1990 Porsche 944S4 with a bad sensor, was flat eating pads on that one corner. No codes, we replaced almost all of the hard parts, finally put the o-scope on the sensor and spun the wheel. Patern wasn't a nice sine wave like you'd expect, was 100% garbage. Computer thought that wheel was sliding and worked the hell out of the abs. New sensor fixed it.

Just remember, if it's new, that just means it's untested. SCOPE IT!!! :flipoff2:
Click to expand...

This !
 
4x4mechanic said:
I had a customer's 1990 Porsche 944S4 with a bad sensor, was flat eating pads on that one corner. No codes, we replaced almost all of the hard parts, finally put the o-scope on the sensor and spun the wheel. Patern wasn't a nice sine wave like you'd expect, was 100% garbage. Computer thought that wheel was sliding and worked the hell out of the abs. New sensor fixed it.

Just remember, if it's new, that just means it's untested. SCOPE IT!!! :flipoff2:
Click to expand...
Have had that happen too, but I don't have a scope.
 
Bebop said:
Super common on rusted out shit that the tone ring is also a big crusty and the gap is too important.
You need to look at the trace with a scan tool.
Click to expand...

I installed a new CV axle, so the tone ring should be the standard parts store chinesium. Shiny, covered in a light coat of oil.
 
Pony_Driver said:
I installed a new CV axle, so the tone ring should be the standard parts store chinesium. Shiny, covered in a light coat of oil.
Click to expand...
Machined to perfection with 0 deviation from the standard OEM tolerance.
Just like the chinesium sensor you put in it.

Pony_Driver said:
Have had that happen too, but I don't have a scope.
Click to expand...
Time to buy the proper tooling, to shotgun other parts at it or just pass it along.
 
Bebop said:
Machined to perfection with 0 deviation from the standard OEM tolerance.
Click to expand...
Oh piss off with that Europoor engineering attitude. Ray Charles can plasma cut out ABS tone rings and have them work fine.

If it were some bajillion tooth diff tone ring with tiny little teeth or some tone ring in the trans that's going super fucking fast it would be a different story but tone rings at the wheel really don't matter as long as they're not packed full of ferrous garbage. If he has a sensor problem it's almost certainly either the sensor or the gap.
 
Pony_Driver said:
didn't do the brakes, but the hose was twisted, not kinked. I reinstalled it correctly without the extra twist.
Click to expand...
if it doesn't quit having a hot brake with the hose straightened out then you probably wrecked the hose and need a new one
 
Rotors don’t warp, you likely have a material transfer issue running an OE formulation of ceramic. But that is likely a result of your hydraulic issue (heat)

Test sensor because aftermarket can cause issues. I’ve had enough problems with aftermarket CV axles I wouldn’t put it past a poor tone ring either
 
[486] said:
bro, what
do you not understand that jimjim spent a whole month at school learning how to measure rotor runout?

maybe in autodesk material analyzer they don't, but
Click to expand...
When is the last time you’ve seen a warped rotor on a Ram 2500? Or anything semi metallic?

I can upload a bunch of pictures off my work phone if you want to see how a rotor “grows” from ceramic material transfer
 
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