Poor brakes and judder through pedal

[RBG21]

Hi everyone,
Good news is the front axle seals are all done and rebuilt and diff sorted, although actuator is going to need rebuilding at some point.
Now the brakes are really not that great and get a bit of vibration through the pedal when coming to a stop, it feels like the ABS coming on but it isn't as braking force isn't usually that great when it happens.
I'm hoping the brakes just need bleeding? and will probably get to it over the weekend.
Has anyone else had this happen on theirs?.

 

[Michael80]

Hi,
I have had the pedal pulsing under braking and coming to a stop, it was one of the raised parts of the tone ring missing. This was confusing the ABS.

 

[RBG21]

Hi,
I have had the pedal pulsing under braking and coming to a stop, it was one of the raised parts of the tone ring missing. This was confusing the ABS.

Thanks, that does sound like a possibility, especially as the whole front has been apart, did a new ring sort it out on your one?.

 

[LandLocked93]

Sounds like warped rotors to me.
But then came across a YT video (didn't watch it) that claimed warped rotors weren't possible. To which I say, BS.
At any rate, have the vibrations come on all at once, or over time?
If over time, prob a rotor issue...that could be caused by a sticky piston.

 

[Beastrider]

I’d suggest checking the runout of the rotors using a dial indicator if you have access to one. Runout can be caused by warping of the rotors (which is definitely possible) or DTV - disc thickness variation. It can also occur if the hub or rotor mounting surfaces had any debris on them during re-assembly.
ABS pulsing feels quite different to brake rotor vibration in my experience.

I would doubt that bleeding will help with the vibration issue but it’s easy to do, so you can eliminate that very quickly anyway. If there is significant air in the circuit, you’ll know via long pedal travel and the pedal feeling spongey.

Of more concern is that you said the brakes were ‘not that great’ - sorting that should be priority. One or more caliper pistons could be stuck, which would reduce the braking effect. Does the vehicle pull to one side during braking? It could be that pads/rotor surfaces are not very good. Are they new? Do you know if they are Toyota or another good make?

 

[frank rabbets]

Variation in disc thickness OR rough patches on the discs. Worth quoting from Toyota. They were cheapest a few years ago.

 

[RBG21]

I’d suggest checking the runout of the rotors using a dial indicator if you have access to one. Runout can be caused by warping of the rotors (which is definitely possible) or DTV - disc thickness variation. It can also occur if the hub or rotor mounting surfaces had any debris on them during re-assembly.
ABS pulsing feels quite different to brake rotor vibration in my experience.

I would doubt that bleeding will help with the vibration issue but it’s easy to do, so you can eliminate that very quickly anyway. If there is significant air in the circuit, you’ll know via long pedal travel and the pedal feeling spongey.

Of more concern is that you said the brakes were ‘not that great’ - sorting that should be priority. One or more caliper pistons could be stuck, which would reduce the braking effect. Does the vehicle pull to one side during braking? It could be that pads/rotor surfaces are not very good. Are they new? Do you know if they are Toyota or another good make?

The discs looked in pretty good shape and the pads have quite a bit of life left in them.

They do work and stop the car ok but there is definitely long pedal travel and they do feel spongey like you say so that’s why bleeding was the first thing that popped in my head.
It doesn’t feel like a sticky calliper to me going from experiencing that on another car in the past.
The pedal pulsing definitely feels like ABS to me, there is no ABS warning though, the ABS ring does sound like something worth investigating as it’s all been apart recently and something might not be quite right.
I’m going to bleed the brakes this weekend to eliminate that at the very least.

 

[Michael80]

The pedal pushes your foot up along with the sound of the ABS working when the tone ring is damaged, no vibration to the steering or anything as long as the discs are running true.
You could remove the abs fuse and see if it stops.

 

[Dave2000]

Assuming there was not a problem with brake judder before doing the axle seals, then remove the discs and clean the mounting faces (hub and disc) and refit them. You will often see a thin layer of rust on the mounting surfaces (often a thin black layer) if this just a thou thick at the hub/disc face this could equate to to 4+ thou at the outer edge of the disc in just one area, this will give the pulsing you are experiencing. Often rust will sit in the vents inside the disc and drop out as the disc is being refitted trapping the particles between disc and hub faces.

If it is the ABS causing the 'pulsing' at the brake pedal, this can happen if the ABS sensor has not seated properly, again remove and refit, something else not often seen but a possibility, check the thrust bearing behind the hub flange, if this is worn then this will alter the distance between the CV joint tone ring and ABS sensor.

Also as an aside, the circlip on the CV (can come adrift if not seated properly, this will allow some movement of the CV and upset the ABS as well.

Regards

Dave