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Does anyone know what the correct thickness of the pad material should be on the parking brake shoes on a Mk 3 LS400?

Thanks in advance.

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Do you have a problem with a new set or with old shoes?

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New shoes have about 1/8 inch or 4 mm.

John.

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There is no correct thickness the criteria is the parking brake holds the car on a hill or incline .

There are several generic aftermarket suppliers of the shoes and they fit other cars of different makes, so the shoes themselves are not really a priority fit as they are not designed to brake the car as normal shoes would they are simply an holding contact.

A new pair have a thickness of approx 5mm

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Hi guys,

Thanks for your comments. I have a problem with a new set of shoes. I bought some new Lexus rear discs, which my indie fitted and he said that the parking brake shoes needed replacing as well as there was hardly any material left on them. I bought some brembo shoes advertised for the LS400 but when my indie fitted them he was unable to get the brake disc back on over the shoes as there was insufficient clearance i.e. the shoe material seemed to be too thick for the disc to fit over them.

Hence my question about what the correct thickness of the pad material should be. Having looked at the thickness of the material on the brembo shoes, it measures about 3.5-4 mm, so it does not seem from your comments that this is any thicker than it should be for new shoes. Any thoughts on why the discs will not go over the new shoes would be gratefully received?

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17 minutes ago, Colin M said:

I have a problem with a new set of shoes.

As I exepected. There are subtle differences in shoes' shape for models years and models, as far as I remember. Aftermarket manufactures care not much (brembo should be ok, but who knows), aftermarket suppliers advert any [censored] care even less. I suggest to find shoes precisely for you car, for example in https://www.ebay.co.uk/usr/lexusofficialstore or with any Lexus dealer maybe, this is not very expensive item.

Or try to compare old and new shoes for every detail and shape, and adapt new ones if it will be possible.

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The last set I bought for a GS were very thin (genuine part). The garage said they needed replacing, but when the saw the new ones, they realised they didn't (they are only ever applied when the vehicle is stationary, so they never really wear, and hence only need a small amount of material). I'd guess a couple of mm. I'd have though the LS would be similar.

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TBH there’s not much friction material on them even from new and 4mm sounds fine, all I have ever done with mine is give the friction material a good ruffing up with some sandpaper and clean the drums out of dust.

I would assume your mechanic has fully backed off the adjuster before trying to fit the drum over the shoes?

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I'd like to think my mechanic has fully backed off the adjuster before trying to fit the drum part of the disc over the shoes, Steve, but I will certainly ask him! Thanks for drawing my attention to this.

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Steve, is the adjuster that needs backing off the one on the parking brake cables under the car or is there another adjuster on the shoe mechanism? Thanks.

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The adjusters on the shoe mechanism is adjusted after the drums are placed over the shoes .

They are adjusted in sequence and have to be fine tuned or the shoes will bind when the parking brake is released or the car reverses with them contacting  the drum.

The correct way is to fit them in the lowest adjustment position ,fit the drum and then adjust the shoes alternative applications via the cog wheel until they bind then take them back a couple of segments on each cog wheel.

The wheel should turn freely then apply the brake and release and if it still turns freely it is adjusted correctly.

The cable adjustment is there to bring sufficient tension to the first adjustment level of the cog adjustment ,if the cog adjustment is at top and cannot be wound back the cable adjustment is too tight and needs taking back.

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Many thanks, Phil, that is very helpful.

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16 hours ago, Colin M said:

... my indie fitted and he said that the parking brake shoes needed replacing as well as there was hardly any material left on them.

As a number of comments above, if these pads are never subject to friction, then pad depth is not an issue; it might be that the original ones are fine and do not need replacing.

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26 minutes ago, route66 said:

As a number of comments above, if these pads are never subject to friction, then pad depth is not an issue; it might be that the original ones are fine and do not need replacing.

The trouble is that a lot of owners myself included set off with the brake on and this wears away the material very quickly and subsequently the holding power is dramatically reduced.

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The trouble is that a lot of owners myself included set off with the brake on and this wears away the material very quickly and subsequently the holding power is dramatically reduced.

That sounds very weird. You mean you are actually moving before you release it? I’d have thought the majority of folk would be foot on brake, put in drive, release park brake, foot off brake, go.

 

 

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That’s how I’ve always done it plus I hold the release handle out when pressing down the pedal down then release it to avoid ratchet wear.

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Honestly, I use them mostly before MOT and on the MOT. And maybe once or twice a year if I have to park on the real slope. Not only in GS but in any automatic cars. I don't say it is good, as brake mechanisms rusted and stuck easier, but simple I am too lazy and there is no point. The parking ratched or lock in proper designed tranny (don't look in the old jaguars direction) is bulletproof and shiny after 10yr of using without a handbrake. For me this is more secondary emergency brake properly demanded by law, than any parking brake.

BTW this is a madness for me, some people apply handbrake at every traffic lights, etc. Ok, a bit less than pure fail on get into N or P in autotranny at every traffic lights, but still.

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I only ever use my parking brake if parking on a slope...........  very rarely

Can't see the car ever popping out of gear/park unless it's given an almighty wallop ..  and then the parking brake wouldn't be much use anyway I guess:whistling1:

Malc

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I think "popping out of park" is possible only with extreme wear of parking mech or very bad designed tranny, even on a slope. Using parking brake on the hi slope with autotranny is recommended not for safety, but rather for easier release parking ratchet, without the stress or "scars" (probably minor, but still), under weight of the car. In normal cars there is no big deal to release or no damage, but it is much easier (in mediocre designed cars, you simple can not release the parking lock under weight of the car, you break lever or mechanism first, elder jags were infamous of this, old XJs? I don't remeber).

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The car is easy to drive off with the parking brake on if you don't use it on a regular basis because of that I learn't from my Mark1 that it is not needed unless on a slope so I only use it rarely just to stop it seizing up.

I have had these cars for twenty four years so I think I have sorted out whats wierd and what is'nt.

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The car is easy to drive off with the parking brake on if you don't use it on a regular basis because of that I learn't from my Mark1 that it is not needed unless on a slope so I only use it rarely just to stop it seizing up.

I have had these cars for twenty four years so I think I have sorted out whats wierd and what is'nt.

 

 

Touchy

 

To be fair, what you describe in the second answer isn’t the same as how the first answer reads. It reads that as part of normal driving, you set off with the park brake on, it doesn’t read that the reason for that is that you occasionally forget you had it on. Hence my “weird” comment.

 

 

 

 

 

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If you look at the Ls400 archives there were a number of comments on this subject over the years and they all LED down the same path in respect of the driving away with the handbrake applied .That is because its not a handbrake and is in fact applied by the foot,which in itself is contrary to what we all learned in our early days of driving ,we all know the procedure for starting from a standstill especially if one as been driving for 55 years the comments I made were merely illustrating a reason to a poster regarding the fact the material should not wear if used properly.

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If you look at the Ls400 archives there were a number of comments on this subject over the years and they all led down the same path in respect of the driving away with the handbrake applied .That is because its not a handbrake and is in fact applied by the foot,which in itself is contrary to what we all learned in our early days of driving ,we all know the procedure for starting from a standstill especially if one as been driving for 55 years the comments I made were merely illustrating a reason to a poster regarding the fact the material should not wear if used properly.

 

Good grief, I’d already explained the confusion on how I read your post.

 

I am in-fact, well aware of the engagement method of the parking brake, hence why I never once referred to it as a hand brake. However, as you keep trying to imply that as you are older, have been driving for longer, have owned a foot operated parking brake Lexus for longer, and therefore you must be the authority on this subject, I probably don’t need to point out that there is a red lamp (which may be an LED for us younger folk and more modern machinery, but will undoubtedly have been an incandescent bulb when you were a lad) that actually informs you that the parking brake is applied, thus trying to aid you in not driving off with said parking brake applied.

 

 

 

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red lamps eh !      I don't quite remember the 1890's with the chauffeur sometimes having to wave the red lamp in front of the car when moving off ...  hedgehogs had an easier time of it all then no doubt :Jumpy: ... handbrake squealing into the bends, doing wheelies ................. :biggrin:

.............. lighten up  ( forgive the pun ) even in MY dotage I can see that this convo is getting a little exasperating.............. for all you guys

Malc

18 minutes ago, TigerFish said:

there is a red lamp

 

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I thought the red lamp meant I had a willing lady in the passenger seat!

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