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grease on the ABS ring

IRLGW

Well-Known Member
Joined
Dec 2, 2011
Messages
1,074
ok so how much grease is ok to have on the abs rings?

I have been having an intermittent problem with my brakes/ABS it feels as if when the truck is about to stop the abs activates and lets go the lefthand front brake and the truck pulls sharply to the right but its only at the very last second before it stops. I knew my inner axle seal had gone on that side so when I took it apart the swivel was full of axle oil and cv grease and the abs ring was plastered. I also notices small metal filings on the abs sensor and it appears that it may have been in contact with the abs ring. I'm not even sure if the two are problems are related.

has anyone any opinion on the amount of grease if any is acceptable to have on the abs ring.

has anyone had problems with milners hdk CV's being out of tolerance and catching the abs ring. I rebuilt the whole axle including the stub axle so assuming the new bearing is keeping it all central...
 
Milner s cvs may be the issue!
 
Metal filings on the sensor can cause issues as can rust on the reluctor rings which won't be happening all the time the spheres have grease in them. Too much grease is not a problem, the sensor won't 'see' it. Anything metal on, or especially the reluctor ring hitting the sensor isn't good.
 
Making it really basic here - CV grease is pretty immobile. IE it stays put. When you do you front hubs, you will always end up with grease in the ABS track. Once you clean a 'groove' in that grease it won't immediately flow back again.

With new sensors this isn't an issue but with age the magnets deteriorate. Anything between the magnet and the sensor will be detrimental. You might need to pull them a couple of times and wipe them. However, there is another cure. On the older sensors there is a shim. You can remove this and drop the sensor head closer to the ABS ring. Don't worry this is actually in the FSM as an approved option.
 
Grease is not the problem, it is the crap that sticks to it.

Try the shim removal Chris mentioned, if no luck pull the spindle and check the bushing inside, if worn it allows the cv and hence the tone ring to 'run out', the fluctuating signal confuses the ABS sensor into triggering.

Regards

Dave
 
Not wishing to get into a game of opinion ping pong on this, but on a weak sensor, grease does have the effect of interfering with the signal. Certainly metallic particles do as you say Dave of course, but anything that isn't air will interfere. I've built hubs up from scratch where there are no metal filings in there and had to wipe the (old) sensors a couple of times to get things working properly. Whilst also right about the concentricness (a word?) of the ABS ring on the shaft it's not something I have encountered myself. As the units are machined, it would be unusual to have one that didn't run true - but not impossible.

I don't know what the specs for run out on the ABS system are but I have been working on a member's 80 recently where we found the ABS ring had been almost ground off and it was still working just fine. There has to be some latitude in there to allow for movement of the shaft in the tube and of course as it moves in and out when cornering.

I have seen bushings worn into an oval before now, so I think it's a good place to check if removing the shim doesn't work. I prefer the needle roller conversion from the 100 series.
 
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The sensors are inductive pickups. They need to be within a certain distance of the reluctor ring to work and as they sense a variation, i.e. the highs and lows of the reluctor ring, this variation needs to be within a certain tolerance, not sure if this is a set band if you like or whether the system 'self tunes' but if the stub shaft has any play in the bushing and can move closer or further away, then it may drop outside this acceptable band. The problem then arises that the shaft wheeling around could allow the reluctor ring to hit the front face of the sensor causing wear and metal filings at some points, as well as having a gap between at others. I've never known pure grease to have an effect on a magnetic field. Grease with ferrous metal particles most definitely would.
 
Ok so I am getting the idea that clean is good but a little grease splatter shouldn't confuse the system. The problem actually started after I rebuilt the hub last year but I kept putting it down to the master cylinder or air in the system. What I am wondering is how the metal filings got on to the ABS sensor and if it has been making contact with the ABS ring. The sensor appears to have a slight chamfer on one side and the ring look to have light marking. now obviously any contact has been just a grazing. The shim is still in place but I'm worried that removing it may only exacerbate the problem if the HDK rings are out of tolerance.

What I'm thinking of doing is assembling the outer CV into the swivel housing with the stub axle in place on the bench and then fitting the abs sensor to see how close it is. I'm not sure how true the axle will sit but its worth a go? Does anyone know if there is a tolerance for the abs sensor clearance in the fsm?

Secondly to this would the shimming of the top swivel bearing have any massive impact on the abs positioning if it was over shimmed?
 
Ok so without having re-assembled and re-tested the brakes, I have discovered that the tip of the abs sensor has been worn by something but that it wasn't the ABS ring. I did a bench assembly and you can see that there is good clearance between the sensor and the ring. So next plan is put it all back together and keep the ring clean. Then I will try swopping the left and right sensors to see if the symptoms switch with it. Then I will try removing the shim and see what that does.

Copy and paste of photos does not appear to be working today
 
This from over seven years ago from my own car, the wear I was referring to is the bushing inside the spindle, the 'run out' was enough to wear an edge on the CV joint also seen in the picture, post number 48 on this page.

https://forum.ih8mud.com/threads/my-lc-80-thread.365673/page-3


FWIW seriously, if you have a sensor that is affected by plain grease you need a new one I mean, the tone ring is submerged in grease by design.

Regards

Dave
 
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FWIW seriously, if you have a sensor that is affected by plain grease you need a new one

Some of these are over 20 years old now. In fact most are. Not sure why this is news.
 
Some of these are over 20 years old now. In fact most are. Not sure why this is news.

Your right Chris, it might not be news to you or me however, it might be for someone else who has does not have our experience.

Regards

Dave
 
Of course, point taken Dave.
 
the point of the exercise is to ascertain whether or not the grease was a contributing factor for the abs problem. However having consulted wang at fsm. I think my problem is the no4 type? Now can a greasy ring cause a no4 type? will be the subject of my phd... The Gap looks too big as well but a spin on the oscilloscope will put that one to bed. of course it could be the vds under the d-a-s-h but will have to wait for my Toyota abs sst to arrive from the states
 
Just to jack up the metal particle theory my ABS played up when the king pin bearings wore. I think due to metal particles stuck to the magnet this allowed false readings. Cleaned and rebuilt the hubs and no probs since.
 
For what it's worth I just rebuilt my front axle and on removing both ABS sensors the ends were covered in grease . The ABS was functioning perfectly , one sensor did have a few bit's of metal stuck to the end .

I wonder if the loom to the sensors tends to work harden or break down over time .....hence Toyota and the aftermarket manufacturers all only supplying a kit of 2 sensors and the loom .

When fitting the sensors make sure you apply grease or Vaseline to the sensor O ring and coat the cleaned bore of the ABS sensor hole with the same , this will keep it free from rust and enable the sensor to be removed without it breaking around the O ring groove as you pull up and twist to remove . One of mine did exactly that and on inspection the bore of the hole was rusty down as far as the O ring .
 
Taken two out myself today and it was like an episode of Time Team. I had to dig them out.
 
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The FSM surprisingly doesn't give a sensor to rotor but other vehicles have specs of <1mm So the next steps in the diagnosis will be

To remove the shims and re test.
check short circuit between pins Tc and E1 of the check connector.
Jack the front of the truck up and check voltage/pulse from speed sensors
Jack rear of the truck and repeat. Maybe I am better to do as L/R due to 4wd?
Test front and rear brake pressure.
Take the Deceleration sensor and throw it violently out the window towards the front of the vehicle whilst braking to make it think it is still travelling at speed. Must fit long extensions beforehand.
Plug in SST and read faults codes if all else fails..
Change the Milners MC for a Toyota one
Put a sticky note on my PC to only buy genuine parts.
 
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