LS430 parking brake adjustment

[Tomtit]

After last year's MOT test the tester said that the parking brake was out of balance and ideally needed adjustment. (I had recently replaced the parking brake shoes). This year to adjust it I followed the workshop manual procedure which said to tighten the adjusters until the wheels lock then back off the adjustment by 7 notches. I did this and had my first MOT fail for many years. The tester said the reading was just over 100 when it should have been 200.

I brought the car home and set about adjusting again. After 3 episodes of putting on axle stands, wheels off, adjust, wheels back on, take off axle stands and test drive, I was getting nowhere. The parking brake would not hold the car.

I adjusted the brakes again until the wheels were locked and the car struggled to move with the parking brake on. For attempt no. 5 I backed off the adjusters by only one tooth. I took the car for a retest and it passed with a reading of 200.

Hopefully my experience may help others.

[steve2006]

I once had an advisory for the 1994 Celsior with parking brake efficiency only just met, strangely he used to test the car as a LS430.

I didn’t replace the brake shoes but merely roughened them up with some course sand paper and same with the inner drum surface.

Then followed the same adjustment procedure. The pedal travelled half the prior distance and locked on the brakes.

Never got another mention on following tests

[Yingyz]

Funny thing because I just failed my MOT because of parking brake below 50% efficiency. 
 

Going to get it looked at but hoping it just needs adjustment. 

[Razor61]

I did a post about doing the rear brakes on my LS400 recently and it includes the extract below from the manual for ‘settling parking brake shoes and discs’ or ‘bedding in’, maybe it’s the same for the LS430.

https://www.lexusownersclub.co.uk/forum/topic/148138-ls400-rear-brakes/
 

[steve2006]

I’d like to know how you apply a force of “147 N ( 15 kdf, 33 lbf)” whilst driving the car?
Perhaps there is a Lexus “Special tool” available for measuring this at a cost of more than the car is worth.

[steve2006]

21 hours ago, Yingyz said:

Funny thing because I just failed my MOT because of parking brake below 50% efficiency. 
 

Going to get it looked at but hoping it just needs adjustment. 

That’s weird because the MOT requirements are quoted as 

“In the UK, a vehicle's parking brake, also known as the handbrake, must have an efficiency of at least 16% to pass an MOT test. This means the brake must be effective enough to keep the vehicle stationary on an incline.”

[Yingyz]

6 hours ago, steve2006 said:

That’s weird because the MOT requirements are quoted as 

“In the UK, a vehicle's parking brake, also known as the handbrake, must have an efficiency of at least 16% to pass an MOT test. This means the brake must be effective enough to keep the vehicle stationary on an incline.”

Maybe they’ve changed it but from the MOT certificate:

• Parking brake efficiency less than 50% of the required value (1.4.2 (a) (ii))

[steve2006]

That would suggest that yours is only 8% efficient or less then?
So 16% would be a pass and possibly an advisory like I once received, below 16% it then becomes a minor defect fail and then a major defect fail below 8%.

Confused.com

[BigBoomer]

I assume that what it means is that you can park on a 16% incline and the parking brake will hold it there.
Simply put, if you apply the parking brake on a steep incline (the steepest you can find in your area) and the car stays put, then it should pass. 
If the parking brake does not hold it, then it will fail the MOT test.
Admittedly it is difficult to test that here in Essex where a 10% gradient is rare, let alone 16%.
However, if you live near Porlock (25%), Hardknott (30%), or Ffordd Pen Llech, Harlech (37.45%) then you will have excellent brakes. 🤣

[Malc1]

in reality, does anyone ever use their Parking Brake ?  The only time it's used on my cars is when I collect from the garage after a service whatever ,,.... and then I usually forget it's on until I see the orange ( or is it red )  light telling me

Mind you I so rarely ever get to a hilltop to park on these days

Malc

[DomTurner]

2 hours ago, BigBoomer said:

if you live near Porlock (25%)

I've taken the LS up there quite a few times now - going up is effortless as expected, providing you aren't following someone unfamiliar with the route.

Never tried the parking brake on it though! I suspect it wouldn't hold as it certainly needs adjusting too.

[BigBoomer]

My parking brake gets used when I park on a slope.
Doesn't happen very often here in Essex, but some of my family live in Harrogate and my better half's family are in the Peak District so it gets used when we visit.

When parking on a slope, I put her in Neutral, apply the parking brake, then ease off the foot brake until I am sure that the parking brake is holding the car, and only then do I select Park.

The scariest part of Porlock Hill in the LS is the narrow bit at the bottom, especially when you encounter a bloody coach coming the other way 🤣

 

[Yingyz]

I’m getting the parking brake looked at today. Hopefully just needs an adjustment and I can be on my merry way.

I did read in the manual if you use the parking brake frequently in a short period of time it will lock you out to prevent overheating the motor.

So maybe the tester turned was a bit too enthusiastic? 
 

Edit: Mechanic has adjusted the parking brake, said the driver side needed 12 clicks vs the passenger side needing 4 and was probably because when the rear discs were changed previously they never adjusted the parking brake. 
 

Manual says 2 clicks but mechanic advised as the car ages the parking brake tends to have more friction so advised 4. 
 

Makes me question what kind of brake job the dealer did as the car had full Lexus history until I bought it 2 years ago and I haven’t changed the rear brakes.

[BigBoomer]

Just because it was the Dealer that did the brakes, doesn't guarantee that the job was done correctly.
Sounds like they reset both sides before fitting the new discs, and then forgot to set one side and didn't check the parking brake.
All that "Dealer" service guarantees is that they will use "genuine" parts.