Brake issues

[larry200]

Hi everyone, new to this forum - refugee from LCOOL.

Had a minor shudder when applying the brakes. Also was somewhat intermittent. Having over 100k on the

clock a lot which were done towing a big van, I thought I may have warped a disk. Checked them with a

dial gauge but no useful info.

Bit the bullet and replaced all 4 with new slotted rotors and pads from DBA. Huge difference in braking. However the shudder

has return almost with a vengeance. Thought I fixed the problem when I disconnected the ECU for another

unrelated issue. ECU is remapped, car went in limp mode and could not clear it with the scangauge.

Problem not fixed and I am lost as to why this is happening. Plan on visiting Berima Diesel later on this year

to have the injectors checked and I'll get them to look at the brakes if I still haven't figured it out.

Any suggestions would be welcomed.

Thank you  

[larry200]

BTW forgot to mention that there is no shake in the steering wheel. The 'shudder',

really hard to describe but almost like brakes on and off. Cannot identify front or rear

or both. Got me totally miffed. 

[larry200]

UPDATE.

Got in contact with DBA, explained the problem and they asked for pictures of the rotors.

These were supplied and the response was slight pad deposit which would cause 'DTV'. That is the

technical term for Disc Thickness Variation. Why would I have that? Vehicle has travelled 30K km

since the brakes were changed, easy driving and no towing. Was I suppose to use DBA pads instead

of Repcos. No mention anywhere that this is the advice - website, box etc.

In desperation had a conversation with a chap at Autobarn who seems to know his stuff, not just a salesman.

His comments were that rotors are more prone to being damaged than discs with a built-in hub. Reason being

that if they do not sit 110% flat against the hub or that wheel nuts have not been tightened correctly damage

could happen. Whenever I have taken the wheels off, the wheel nuts are torqued to 140Nm and in the correct

sequence when re-installed. Who knows what happens at a tyre shop. Apparently even a minute spec of corrosion

on the hub could cause this. What a lot of BS I thought. So, pulled the brakes off again for the third time in as many days

and took them to a machine shop.

Cut a long story short, they required an ever so slight amount of skimming. After 30,000 kms? Thickness of pads

is 1 mm, yes 1 mm, less than new. So when I say easy driving, I mean easy driving. Most of the shudder has gone now.

I say most because the rears probably will require skimming.

Am I looking at going through this whole BS 30,000 km from now?

BTW, also got a lecture from DBA about not using a 'qualified' mechanic. So I asked, what would this so called 'qualified'

mechanic have done different. And where do you find one? Certainly not at a Toyota Stealership.

[Gordo2]

Shudder in 200 series can & will come from a over adjusted hand brake shoes & cables.

Jack up under the axle un adjust the hand brake cable in cab then back off the hand brake shoes then readjust the shoes so the wheel turn freely then adjust the cable in cabin just enough for it to hold at with about 6 clicks too tight causes shoes to drag.

[larry200]

Thanks for that but handbrake hasn't been touched in over 50,000 kms. Last time was when the

car was serviced at a Toyota Stealership ( fixed price) and they over tightened it.

[Gordo2]

Fitting new new rear rotors without adjusting the the shoes to the new unworn diameter is asking for trouble with overheating the rear rotors causing distortion I have worked in the brake industry for about 40 years & what I don't have an idea about what's going on is not worth knowing.

Dtv can come from machining practice from new to in field machining as well as installation procedure & what to look for prior to fitting.

Ray.

[larry200]

No handbrake on front rotors. Will get the rears done soon. My take on this (time will tell) is that the castings have not cured/seasoned

enough when fitted. Similar concept when in days gone by when building a race engine (NASCAR) using a cast iron block. Wisdom was

to use a 'used' block or leave the new one out in the weather for 12 months to cure/season.