Vibration when braking

[TSTOY]

I've got a 2004 3.0TD Hilux & am experiancing vibration when applying brakes. The vibration seems more apparent when carrying load, & can be felt through the brake pedal.
Recently replaced brake pads, machined discs, re-pack front wheel bearings (yeah I know, obviosly).:D

The problem didn't exist after work was done but came about later. Today I pulled all wheels off & checked drums & discs for any apparent distortion. Also checked that front wheel bearings were not loose. Everything seems OK so its got me a little stumped.

Anyone have any ideas or experianced this personally?

Thanx.

[HiCountryCruisr]

Try changing wheels from front to back. A weight may have fallen off which will make it go out of balance. If the vibration goes to the rear, you know its the wheels.

[A1 Mech]

Sounds to me as tho one or both of ur front rotors is warped to a degree or has glazed spots on its surface causing varying degrees of friction as it rotates thru the caliper. Machining is only so fool proof, Does the car pull to a particular side if u simulate the shudder with no hands on the wheel? This cud show which side is at fault. It cud be time to upgrade to a set of DBA slotters. Cheers

[sexylux]

vibration through the pedal/seat while braking means that the rear drums need to be machined and/or shoes require surfacing/radius grinding, vibration through the steering wheel means front discs need machining.

[A1 Mech]

I doubt that on an 04 lux unless it has high km's or a dragging drum that the drums wud need machining. shudder can be felt thru the pedal wether it is front or rear. Both bias r hyraulically linked to the master cylinder and brake pedal. A rotor does not hav to be old or worn to be warped, hitting a decent puddle on the road just after heavy braking can warp ur rotors instantly.

[Sic Lux]

I'd put money on the rear drums need machining.

[TSTOY]

Thanx for the replys fella's.

The vehicle I don't think pulls to the side under braking, but I'll test it properly on the drive home from work tonight. Tomorrow I'll back off the adjusters on the rear drums right back & take it for a test drive, & try to eliminate the front or rear. I'll be spewing if its the front brakes, as I said I've already machined discs & done bearings.

Wouldn't an unbalanced tyre vibrate when rolling also? The vibration stops as soon as I take my foot off the brake pedal. Still I guess a tyre rotation is worth a try.

I'll report back tomorrow.

[Sic Lux]

Backing the brakes of will only give you a crap pedal as you need to move more fluid to get the shoes to contact the drum the only way to cut off the rear brakes is to clamp the line with a line clamp i do this crap for a crust i'd be machining the drums and new shoes if they need replacing will fix it every time

[gregu78]

Sounds like you have runout in the front rotors, if the vibration went away after work was done but came back later. Make sure wheel bearings aren't loose. The rotors really should be machined with an on car disc machine, making sure wheel bearings don't have play/not over tightened. Also check the pins that hold the pads in aren't worn, as they may be causing the pads to not "back off" the disc. Also check caliper pistons are not seized for same issue.

P.S. These rotors are cheap to buy new, not sure why people machine these days.

If you want new rotors P.M. me and i'll advise you of a good / cheap reseller near you.

[fullmetaljacket]

if the vibbration is kind of like a "pulse" from the pedal (pedal movement up and down slightly), its gunna be a:- X 3 on your steer rotors being warped, which may not be picked up during off vehicle machining

after you did the inital repairs, by chance you didnt happen to drive through a puddle or wash the rims/rotors when they were hot?

[TSTOY]

Ok, went to ABS this morning where I'd had the discs machined roughly 3K ago. They also reconmended crimping the brake line to isolate where the problem may be. I done this with vice grip pliers & a rag to not damage the brake line. The line was crimped just before it T's off so as to disengage both rear drums.

Took the vehicle for a test drive & the vibration was still presant. Un crimped the brake line & test drove again, this time using the hand brake to engage the rear drums( don't know if this is really a good indicator), but there was no vibration when the rear drums where activated.

So it seems the problem may be in the front. Had the calipers off the discs yesterday to make sure there was no play in the wheel bearings, all seemed Ok.

Looks like I may be up for new rotors :cry:, maybe. Never had this problem before machining the discs. Could machining cause this problem?:confused:

Headed bush after the work was initially done. Engaged 4WD a couple times but nothing hardcore, & crossed no water. So its got me stuffed how the rotors could have warped, if thats what the problem is.

gregu78, PM'd you about new rotors.

[A1 Mech]

Like I said may be time to upgrade to slotted/vented rotors. They r pretty cheap these days for the hilux. Ther isnt a whole lot else it cud be on a 4yr old IFS toyota.

[Sic Lux]

Ok, went to ABS this morning where I'd had the discs machined roughly 3K ago. Did they dial the rotors up to see if there was exessive runout in the rotors or just tell you a few things to do to try find out where it is might pay to ask them if they could do that that'll tell you 100 percent if it's that or not. Also what pads did they fit the bendix ct's were having alot of problems causing brake vibration had a hew friends trail them and they ended up shaking.

[TSTOY]

The pads fitted to the vehicle are Lucas. Dont know what process was used to machine the discs. I just took them into the shop when I noticed the pads wearing low & asked them to be machined. I've had the vehicle since new & this was their first machining. Checked the disc thickness with a caliper & it was within spec. Didn't expect a problem, I've done this before on prevoius trucks. But I'll have another chat to them tomorrow.

I've heard slotted rotars are the way to go, but have no experiance with them. On a 4WD thats often offroad doing bush trips, do you think there is potential for the slots on the rotars to fill with grit/dirt & contaminate the pads? Maybe causing premeture wear on the pad/disc assembly. Or is this not likely?

[A1 Mech]

Ther is no problem running a slotted rotor on a 4x4, the slots actually help to keep the pads clean. Its crossed drilled that u wanna steer clear of as they can fill with dirt and when driven into water hot can crack between the holes. I hav had slotted/vented DBA rotors on my 4runner for about 4mths now and they perform well.

[TSTOY]

Well thanx to gregu78 & the boys at Northern Brake & Clutch in Melb, I was able to source two new RDA rotors for the hilux. Ended up going for non slotted standard rotors, they were cheaper.

I bought a dial indicator as i wanted to check the runout on the recently machined discs, & I got a reading of 0.31mm. The workshop manual lists maximum at 0.07mm. After installing the new RDA rotors I checked runout oncemore for the following readings; left 0.02mm, right 0.03mm. Took the truck for a test drive, & while not braking hard (allowing pads to bed in) I could tell allready that there was no vibration.:waycool:

Dont know if I'll machine discs again after this experience, when for a little more than a machine job, you could just buy new rotors.