Landcruiser Brakes

Submitted: Thursday, May 20, 2004 at 07:37
ThreadID: 120588 Views:2245 Replies:11 FollowUps:0
This Thread has been Archived
I just had a service on the 100 series and they
advised me my rear pads were worn and needed replacing, or at least down to 20%
left. Normally I have to replace the fronts before the rear, but I have still
got 40% left on the fronts.

They think that this is odd too, and normally 2
fronts for each rear.

I checked with them in case the higher rear springs
had an effect, but there is no proportioning valve.

I also checked and have definitely never had the
fronts done.



I’m not worried about the wear, as it was a
130,000km service, but I trying to work out if my brakes are working correctly.

Anyone had this experience.



----------------------

Gary Harding

TriSys Engineering/III





Back Expand Un-Read 0 Moderator

Reply By: Deleted User - Thursday, May 20, 2004 at 07:39

Thursday, May 20, 2004 at 07:39
My Landcruiser has only done 55,000km and brake replacement is still a long way off yet, so can't comment on whether this is common to other owners. However, a thought is that brake pads usually come in various grades (others will know the technical description, but I would just describe the grades as varying from soft-to-hard). Perhaps the front pads were of a different grade, maybe even a production anomaly, and hence the wear rates are different. The other possibility, though remote, is if the handbrake has been over-adjusted or somehow misapplied, and is causing the slightest drag on the rear)? It's a mystery, that's for sure. Phil
AnswerID: 562286

Reply By: Deleted User - Thursday, May 20, 2004 at 07:40

Thursday, May 20, 2004 at 07:40
Most premature wear in the rear can also be attributed to the pad not releasing off the disc after the pedal has been released. The cause is usually dust accumulation or rust on the slide pins or whatever system retains the pads. The back brakes get more crap on them than the front because the front tyres toss the crap straight to them. Rear handbrakes are not usually acting on the disc pads but rather a separate drum system. Pads these days are very environmentally friendly, wear much faster as a result and they are very soft in comparison to older types. This is why pads now put a dirty black coating on wheels very quickly. These softer pads do save a fair bit of disc wear and the pads are cheaper than disc rotor replacement. The modern disc rotor from OEM's dont have a very high tolerance for disc wear and most are a throw away item when worn. So ...keep the pads soft if you like .... ! Pad composition certainly helps. Trouble is the disc wear increases with pad hardness. Also ...hard metallic pads take some time to warm up so the first stop or two braking effort is increased. Their major advantage is they dont fade as fast as a soft pad so are much better for towing. I usually compromise with my pads ...I wear the originals out and then go for the next hardest pad composition from original. Might be listed as a towing pad or 4x4 pad etc. Gary, Give the brake calipers a good clean ... especially in the area around the pistons and pad retaining system. Maybe the mech that did the brake service just chucked the pads in with little cleaning ??? Your disc rotors getting to 130k without machining or replacement says the pads are soft composition. We expect the brakes on large 4x4's to be like cars but we load them up to the hilt and them chuck on a BT so they sure cop some punishment. You've done well to get to 130k on the fronts ..if they are original you must be a light braker ...sign of good driver huh !! [smile] If you are cleaning them yourself use a product called Brake-Kleen. It is a highly volatile solvent that when dry leaves no residue on discs etc. Would be best if pads are removed first. If you need to clean pads with brake-kleen leave in sun for half hour to evap solvent. If any retaining pins are marked with shoulders they should be replaced and if not cleaned with solvent and a scotch brite if rusted.. New split pins are a must. One 4x4 I had over-used rear pads as well .... I thought of disc speed difference at pad area because of diameter difference from front to rear ...pad area verses applied piston pressure ... disc rotor runout not enough to push pad away after braking etc . All it was .... the pad retaining pins were worn, clogged with mud and brake pad dust ..... If all seems clean might pay to check at a reputable brake shop. Anthony Explore this Great Land ..Do it Easy ...Tow a bushtracker
AnswerID: 562287

Reply By: Bushtracker42 - Thursday, May 20, 2004 at 07:41

Thursday, May 20, 2004 at 07:41
Anthony.



Re “Maybe the mech that did the brake service
just chucked the pads in with little cleaning”
I only just replaced the original rear pads this week, so no mechanic
(good dealer by the way) has touched them at all before. The front pads
however will be doing 170K plus by the look of it.

I took the wheels off myself today and no scoring on
the discs, so does not look like undue wear/dirt. I expect the discs to see another
250K before machining (3-4 years for me).



I am a light braker, or is it I just don’t brake
…..









----------------------

Gary Harding

TriSys Engineering/III





AnswerID: 562288

Reply By: Deleted User - Thursday, May 20, 2004 at 07:42

Thursday, May 20, 2004 at 07:42
Gary, Make sure you are not driving with the handbrake slightly on as I have done that before because the missus doesn't look at the idiot lights. Regards Macka
AnswerID: 562289

Reply By: Bushtracker42 - Thursday, May 20, 2004 at 07:43

Thursday, May 20, 2004 at 07:43
I’m starting to think maybe they adjusted them
up too much on one service.



This may also explain one other thing.

1st trip with the BT we typically did 16-17
litres/100km on the open road

2nd Trip’s average 19l/100km, but
put this down to me using the foot a bit more/more confident.

We did a trip up to drop off the BT for hail repairs
and we average better fuel e.g. 17-18l/100 and I was siting on the 100-105
km/hr. We put it down to the Diesel running in and having the lighter
resistance road tyres/mags rather than the 4wd/steel rims on.



Maybe I cat get up Mt Ousley in 3rd now.



----------------------

Gary Harding

TriSys Engineering/III





AnswerID: 562290

Reply By: Deleted User - Thursday, May 20, 2004 at 07:44

Thursday, May 20, 2004 at 07:44
G'day Gary, I assumed we were talking about rear disc brakes here !! Do you have drum brakes on the rear ??? If disc .... there is no adjustment able to be done on disc brakes. There is adjustment at the pedal used to attain a small freeplay in pedal so master cylinder piston is at the very start of its stroke. If disc ....the handbrake system is usually separate from the disc system. It is housed in a small drum on the inside of the disc rotor and identified by a cable going into the dust plate. Some vehicles use a hydraulic handbrake that operates the caliper pistons on the disc but it is not common. As examples my F250 has separate handbrake system ... as does my new WRX ...as does my new Forester. My 1972 Corvette has rear discs with this separate handbrake also. Maybe the Cruiser has integral caliper handbrake but I doubt it. As I said in the post above most premature rear disc pad wear is from binding in its locating system. In some types it is a pin system, in some types it is a machined groove that holds the pad. As the pad wears it has to move further towards the disc (approx 10mm for each pad) the pins/groove allow this movement. Because this happens over the life of the pad dirt/rust accumulates in the groove and stops the pad moving away from the disc when the brakes are released. All discs have what is called runout i.e. they wobble as you rotate them, it can be anywhere from .001 to .003 of an inch. This wobble moves the pad away from the disc when the brakes are released so the pad doesnt stay against the disc causing premature wear and/or excessive heat. If the pad cant move back because of crap in the groove or pin wear it stays slightly against the disc and wears early. This is usually only seen by removal of the pads and inspecting the area in the caliper on the area at the pad. If drums .... the rear pads (shoes) are used for the handbrake and if adjusted up too far will rub excessively. A small amount of rub is necessary when replacing shoes because the arc the shoes scribe differ slightly to drum arc so the whole shoe surface is not used til they "run-in". Even then brake shoes for drum brakes usually only attain 80 % of total pad surface against drum. Too much adjustment up on drum brakes results in some pad wear initially but the pads soon wear to give a clearance .... if the heat generated doesnt leak to drum cracks or bearing failure from excessive heat. If they are over adjusted every service you will get early wear. If severely over adjusted you would feel it as you backed off the throttle as soon as you drove out of the dealership. If you didnt feel it they could still be overadjusted but would be fine after 100 k's or so. If they are drums they could have premature wear from adjustment every service but not if disc as there is no adjustment. In the case of discs adjustment for pad wear is taken up in the caliper piston travel and hydraulic fluid capacity of the master cylinder over the pads service life. The other reason a pad wears too fast is from a cheap pad or OEM pads that are softer and designed to stop well when cold. Some aftermarket pads have 6-7 pad compositions and dont wear anywhere near the oem stuff. I've worn out a set of rear oem pads of a 4x4 (no towing) in 15,000k. At the other end of the scale the pads I've selected for the WRX are around $900 a set, last forever and will run all day at 600 deg C ...over twice the temp of an oem pad. They are also dustless by comparison. Regards Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 562291

Reply By: Bushtracker42 - Thursday, May 20, 2004 at 07:45

Thursday, May 20, 2004 at 07:45
They are discs.



I have not even checked how the handbrake works. I
used to ‘play’ with cars all my spare time, but around the time
cars did not need points, I got less interested. (Jenny did not enjoy me club
racing as well)



I only looked under the back and saw a cable coming
from the front, spitting into the back of each disc guard. There is adjustments
on it and obviously the dealer could just adjust up the actual handbrake cable
itself too much.

I’ll check it out.

Another 130,000 km will tell.





----------------------

Gary Harding

TriSys Engineering/III





AnswerID: 562292

Reply By: Deleted User - Thursday, May 20, 2004 at 07:46

Thursday, May 20, 2004 at 07:46
G'day Gary et al, I had four diesel Landcruisers since 1980, each doing 150 to 180 k over a 5 to 6 year period. I have never had to have linings, brake pads or discs replaced. I have 12,000 km on a new V8 petrol and am now feeling a little sorry that I didn't stick with the diesel for the following reasons:- Just returned from a 5000k Queensland highlands trip and averaged 26 l/100k with lots of steep climbs (up to 20% grades going into (south) and out of (north) Bunya Mountains, + a lot of low range through rugged country in Expedition NP, Ka Ka Mundi, Savator Rosa and Gooliff. My last diesel would have done this at under 20 l/100k. Going downhill you have to use the brakes a LOT more, on both vehicle and caravan. The diesels have much better compression braking and therefore better response to driving in lower gears. With the petrol, therefore, I will have to watch the brake wear as I don't think they'll last as long. Since ABS brakes were introduced into the Landcruisers, there's a safety issue everyone should be aware of :- When going over rough roads, especially corrugations, hoofugations and cattle grids, the ABS sensors can become confused and bleep !! - momentory loss of brakes! It is very scary and on one occasion near Ka Ka Mundi, we ventured off the track as a result. Could have been disaster in mounainous terrain. (Hoofugations is the name we give to black soil roads, after cattle have tromped along them when it's wet - then it dries to concrete .........worse than any corrugations!!) I have heard of people disconnecting the ABS when on rough roads, or pulling the ABS fuse out. This would probably void warranties and insurance policies though. Perhaps it is something that Toyota should be looking at solving. - In the meantime try to drive in such a manner that you don't have to brake - use your gears and increase the sensitivity in your brake controller so the van brakes come on earlier. Cheers........Rob
AnswerID: 562293

Reply By: Cracker - Thursday, May 20, 2004 at 07:47

Thursday, May 20, 2004 at 07:47
With all th talk on brakes, I thought I'd put in my 2 bobs worth. When I first purchased my Toyota 80 series the mechanic backed off the hand brake cable heaps. I spoke to him about the extreme amount of travel before the handbrake began to bite. He said that the handbrake ( WHICH ACTS UPON THE DISC PAD ) had to have heaps of slack in the line as it would cause excessive wear otherwise. So reading your comments about heaps of wear - I'd say they adjusted the hand brake cable to spec's .....and like the bloke told me - it wore out your pads. I just went and checked mine - it takes 10 clicks before it becomes solid/difficult to move. I use Bendix metal king pads and get 70,000 k's from the fronts. Cracker
AnswerID: 562294

Reply By: Deleted User - Thursday, May 20, 2004 at 07:48

Thursday, May 20, 2004 at 07:48
Hi Gary et al, the rear brake setup used on later model 80 and 100 series cruisers is a disc service brake and drum handbrake. The drum for the handbrake assembly is cast as part of the rear disc rotor. The attached (I hope)picture shows the handbrake being retracted to remove the rear brake disc rotor, the handbrake is adjusted via the same hole. The picture on the right shows the handbrake components with the brake rotor removed. As detailed in the picture, handbrake adjustment on these models has no relationship with rear disc pad wear. Another area that can cause excessive rear pad wear is if the load sensing proportioning valve is incorrectly adjusted. This valve varies the pressure to the rear brakes depending upon the load that the vehicle is carrying, more load = more braking force applied to rear pads. More braking force = more wear.

Cheers Pete
AnswerID: 562295

Reply By: Deleted User - Thursday, May 20, 2004 at 07:49

Thursday, May 20, 2004 at 07:49
I, and a friend who also tows a caravan, have had similar experience. Toyota could not explain it to me. Must be related to weight of van pushing down on rear wheels when breaking.
AnswerID: 562296

Our Sponsors