LS400 Rear Brakes

Razor61 · August 27

Not done much work on the LS400 for a while but needed to spend a few hours on the rear brakes at the weekend and is a lesson to me to 'not put off planned work', don't be a hypocrite and practice what I preach 😄

To set the 'scene':

When I purchased the car, 3 years in December and how time flies, new discs and pads had been fitted all round. Not Lexus/Toyota OE though.
I purchased new discs/pads/fitting kit/anti squeal shims/pad sensors for both front and rear, the original shims were missing.
I replaced the front discs/pads/shims/pad sensor etc. a few months later but figured I'd leave the rears for a while but didn't get round to doing them, first mistake!
The rear pad sensor had been cut and shorted out, I have a new sensor so decided I'd replace it when I did the discs and pads, second mistake!!

What happened:

While driving on Friday late afternoon I heard a 'something catching' sound on the rear when turning left at a junction, sounded like the drivers rear, then it disappeared when driving straight.
I suspected a brake dust plate catching a disc, when coming to a stop at my destination it sounded like a brake pad was 'metal on metal' but not really loud.
Drove back home and couldn't really replicate the issue.
Saturday morning took the front wheels off and checked for anything catching rubbing, all ok.
Took the passenger rear wheel off to do the same, discs good, pads ok really, getting low but had decent even wear.
Rears are sliding calipers so checked the slider pins, both pins were seized which is a common problem if not checked and greased regularly. I hadn't done this so is the third mistake!!!
Wasn't in the mood to replace the discs and pads so removed the caliper carrier and, after quite a bit of work, freed up the slider pins.
One was really seized and took ages to free up, but anyway....... everything cleaned up, greased, reassembled, fitted back to the car with the existing pads as they were and the calipers sliding as they should.
At this point, note to myself to purchase new slider pins and seals etc (maybe new caliper carriers) and replaced the discs and pads as soon as possible along with the new pad wear sensor but they will be fine until I do it all.
Removed the drivers rear wheel to have a look and check, one slider pin was seized but the other was ok. Outer pad looked ok but the inner pad was worn wafer thin and was metal on metal on the lower corner.
Of course I've found the cause of the noise noticed the day before.
Although not in the mood for doing it, I had no choice but to fit the new discs/pads/shims etc.
A few hours later new disc/pads/shims fitted and grease applied in the correct areas, parking brake shoes adjusted as best I could, wheels back on and wheel nuts torqued up.
All good and chuffed with myself, walked back in the garage and saw the new pad wear sensor lying on the bench 😠 not happy but that can wait until I get all the new slider pins and seals.
A lesson learned, and the rear caliper sliders will be checked on a regular basis and greased which is something IS250 owners know all about.

Braking is a lot better now, I can feel the rear braking and it brakes level rather than the front dipping down.
I have said in previous topics that owners don't notice gradual degradation in suspension and brake type stuff and it's not until someone else drives the car that they notice, this is a prime example (slightly different but same principle) and has happened to me when I didn't think it would ☺️and I'm suitably embarrassed.

I still have the slider pins and dust seals etc to order and fit along with new parking brake shoes, which I have already, but after that it's back to trouble free motoring for a while.

ambermarine · August 28

Brake maintenance is critical to us Diy owners who do not use dealership servicing,I did my fronts last week and although I have only done 8k since they were last serviced it is amazing how much brake ditritus builds up around the pistons and moving parts.the other benefit of having the wheel off is being able to access the suspension parts and the upper wheel arch.

On closer inspection there was surface rust apperaing on control arms and the upper control arm body anchor brackets mainly from contamination off the arm.

A quick wire brush action and primer paint on all these surfaces followed by a liberal dinitrol covering and we are back to factory finish.

Razor61 · August 28

Yep, I neglected the rear brake maintenance and didn't check the rears when I bought it.
Unusual for me but you could see the discs and pads were new and that probably lulled me into a false sense of security, I know better and there is more to just changing discs and pads for brake maintenance.

Some other stuff on this.
The aftermarket disc centres were all rusty, not paint/coating on them, so didn't look nice at all.
The Lexus OEM discs are better quality and have a nice black coating on the centres which looks nice, how long that lasts who knows but I'd guess it will last a long time.

Anti-squeal shims/plates were missing along with the 2 x anti-squeal springs on each side.
After everything was back together with all the correct stuff, no noise with the pads moving about when slowly reversing off the drive.
Sounds a minor thing but it was annoying.
I bought a 'fitting kit' from Amayama which consists of the pad clips and Anti-squeal springs along with other stuff a long time ago ready for the job.
I lost or mislaid one of the pad clips so used a 'used' one off the car, thought about ordering another fitting kit along with the slider pins and other stuff from Amayama but didn't in the end.
Just out interest I looked on LPD, current Amayama price for the fitting kit - 04948-30050 - is £24.43 plus shipping, still not exactly cheap for 8 clips and 4 springs.
Price for the same thing in the UK from LPD website...............................£188.69, I know UK prices are higher but nearly 8 x times the price?
Surely it must be a mistake, the front pad fitting kit is 'only' £44.48 from LPD.

MerchantOfVenice · September 3

Guys is there a diy anywhere on how to change the discs and pads on a ls400 please?

Many thanks

cruisermark · September 3

2 hours ago, MerchantOfVenice said:

Guys is there a diy anywhere on how to change the discs and pads on a ls400 please?

Many thanks

You could use this video as a reference:

ambermarine · September 3

Save yourself a few quid on the sensor just solder a piece of wire on to the two terminal ends,therefore reinstating the circuit.

Razor61 · September 16

Some more info on this concerning the parking brake adjustment.

Attempt #1

After replacing the discs I adjusted the parking brake shoes using a method I've used in the past for cars with brake shoes rather than disc/calipers at the rear, adjust the shoes until they bind then back of so they are just rubbing/catching.
Parking brake wouldn't hold, even though I attached a couple of wheel nuts - applied parking brake and used a 2 foot pry bar to try and turn the wheel/s.
So consulted the manual and tried again.

Attempt #2

Rear off the ground using 2 x 3 ton trolley jacks, both rear wheels off the car (all done safely with front wheels chocked front and rear)
Adjust the parking brake on both sides so they are both engaged - back off the adjustment 8 'notches or clicks' on both sides.
Attached a couple of wheel nuts - applied parking brake and used a 2 foot pry bar to try and turn the wheel/s and all good I thought.
Wheels back on etc and tested, still not holding, what am I doing wrong or what am I missing?

Attempt #3

Had a think about it some more, looked at the manual again and then the penny dropped................new discs and therefore the parking brake 'drum' needs 'bedding in' to the parking shoes.
How thick am I ????.......🤣
For cars with brake shoes rather than disc/calipers at the rear, the shoes will bed in as normal because they are being used when the car is moving of course but the parking brake isn't.
Below are the instructions for 'after' replacing the parking brake shoes, I adjusted them ok but then didn't do the 'settling in....' bit at the end because I hadn't replaced the parking brake shoes.
However, discs are new so the same principle applies of needing to 'bed them in' to new discs.
I was a bit apprehensive of applying the parking brake while travelling at 30mph for 400 yards, gauging 147 n of pressure and repeating it a few times more but I did it this morning on the way to work and parking brake now holds ok and as normal.
It all makes sense now and I won't forget in a hurry, it's now ready for the MOT in a couple of weeks and will maybe help others when they replace the rear discs/pads and or parking brake shoes and then find the parking brake is Cr@p and doesn't hold.