cathastrophic brake failure

[SpinDrift]

Ive had a complete brake failure on the 100 series - brakes completely gone. Thankfully this happened on the drive way and not on some mountain pass!

The ABS and brake warning lights have come on and the warning buzzer is sounding. This seems to indicate that the issue is the electic servo pump on the underside of the master cyclinder. A quick browse of the internet shows that this issue has been known to happen with 100 series of a certain milage - I'm currently at 225k miles.

According to Toyota, the servo pump is not a servicable item and is part of the master cylinder - complete unit needs to be changed at a price of some £2.5k, and that is without labour. There are posts on mud and on an other forum that tell of the pump motor being stripped and rebuilt (rewired) by a specilist company. Given the nature of the trips I go on, I will be replacing with new but will be sourcing, shall we say, elsewhere. A used unit is not really an option as it is also likely to fail unexpectedly.

It would appear that there is no preventative maintenance that can be carried out on the motor to prevent this failure, and when it happens it is sudden and without warning. I would suggest to anyone using a 100 series with similar milage on a trip to the back of beyond to either have the motor rebuilt or the whole unit replaced with new - these are the brakes we are talking about. Difficult to limp home without them. I'm sure someone will jump in and say 'get an 80'

And if the brakes failing was not enough - there are some more complications ... I got the company with the big yellow trucks to transport the LC from home to West Coast as I have their home and relay service. As I live on a hill, I put the LC into low range to make it easier to manueovour to the back of the truck without brakes. When I then tried to put it back into high and into park, it refused and stayed in neutral. No doubt the brake falure prompted the ECU to say 'oh no you dont'! Not even into some kind of limp mode.

 

[nick_the_fish]

Sorry to hear about the brake failure. Like you say good job it happened on the driveway not on a steep windy road. In terms of sourcing a new unit, have you tried Amayama? (remember to allow for VAT and import duty when comparing cost).

 

[Higgy]

Bugger.. I feel for ya mate, I had a front end fail and lock up on my 120 while approaching a round about ... Scary.. Luckily it didnt cost £2500 to put right..We take brakes for granted and assume they are gonna work when we need them....I cant remember the last time i had to brake in an emergency...But how many of us actually Test em.... I mean drive down the Motorway at 70mph and leap on the Brakes to test em.. Not me ,Too Scary.. Good job you were on your Driveway...Hope you get it sorted

 

[Jon Wildsmith]

Pretty sure the ABS and Transmission ECU don't communicate so that won't be the cause of being stuck in neutral. Was it the transfer box or main transmission that was stuck in neutral? iirc the main transmission has to be in N to be able to select L or H on the transfer box so e.g. I don't think you can change into H while the main trans is in P it has to be in N.

I think Julian has somewhere he sends the pumps to be rebuilt.

 

[SpinDrift]

Milage wise, this should have happened last year on our way to the Balkans - probably somewhere on the autobahn in Germany. We had a quick change of plan as the windscreen cracked a few days before departure. There was no time to fix it so we changed from a dirt track trip in the mountains to a camping beach holiday in Croatia in the beamer.

I've already had a look at Part Souq and the prices are easily half. I'll hve a look at Amayama as wll but will be talking to Paul at West Coast before ordering anything to make sure we order the right unit.

@jon, I believe both were in neutral but I might be wrong. We were in the process of loading onto the truck at the time and it was the last thing I needed so I dont exclude operator error. I know there is a company in London that rebuilds these motors, but this being the brakes I think I would rather have new.

 

[StarCruiser]

There’s a good chance Robson and Francis can rebuild the motor for you and it will be as good or better than New. Give Mike a call on 020 7733 2353. I have a feeling they’ve done them before.

 

[Deleted member 13129]

Bugger.. I feel for ya mate, I had a front end fail and lock up on my 120 while approaching a round about ... Scary.. Luckily it didnt cost £2500 to put right..We take brakes for granted and assume they are gonna work when we need them....I cant remember the last time i had to brake in an emergency...But how many of us actually Test em.... I mean drive down the Motorway at 70mph and leap on the Brakes to test em.. Not me ,Too Scary.. Good job you were on your Driveway...Hope you get it sorted

One of my front calipers seized fully open when I shipped My truck to Cyprus took 5 weeks in mid winter , driving it home from the port 50 miles down the motorway unaware I stamped on the brakes at about 70 mph as someone pulled out in front of me soon woke me up as it pulled badly to one side , I ended up changing all 4 calipers for peace of mind .

 

[Higgy]

Ah! You see Tony.. Should have tested em first... you could have stamped on them and frightened yourself to Death for No reason what so ever

 

[moggy1968]

£2.5k!!!!
Fuck me!!!!

 

[moggy1968]

That’s really shit design as well, a component failure that causes sudden complete brake failure with no warning is just really crap.

 

[BobMurphy]

It happened to me as well - at the bottom of a steep hill while towing horses . The mileage was only around 130,000 miles.

I nursed it home and replaced the whole Brake/Servo unit with one from e-Bay that cost £300.

I then sent the pump motor from the failed one to 'Robson & Francis Rewinds' who re-built it at a cost of something over £200 (memory going). I now have a fully-operational spare.

The problem was caused by metal fatigue in the brass contacts on the pump motor. I guess the thing vibrates when its running and eventually the power leads part company.

I know what you mean about replacing it with a brand new one and thought long and hard about it. In the end the "Good Used" one was too good to pass up. I inspected it thoroughly and it has been fine.

It is at the back on my mind when its in use and it is a really crap design - like the '90' front balljoints (I had one of them go as well!).

Much as I love my Landcruisers . . They have some serious flaws (Rust being another one, our two RAV4s are almost rust free after 190,000 miles & 12 years, yet my two 'cruisers are falling apart).

Bob.

 

[uHu]

You still have brakes when the booster fails, just that it is weak and requires a strong brake-leg. And the presence of mind to push hard and pull the hand brake as well. (Hand brake also needs PM, btw). It certainly feels like all braking power is gone, but if you press really hard, there is a bit, and only on the fronts.
You do get warnings before you are out of brake pressure, but, if you are like me, you don't always care to much about an irritating sound or some warning light. If the booster is fully charged (if you wait with driving until the warning light is off), you still have 2-3 full power braking strokes available if the booster motor fails, but after that it's nothing (or what feels like nothing). The handbrake is another weak point. It needs annual TLC to perform well. And anyhow, the combined stopping power of main brakes without booster (fronts only) and a not very effective hand brake (rears only) is faar from normal brakes, and far from what i s required for safe stopping.

Some ramblings:
The 3 most common problems with the brake master / booster combo:

1: Electric motor worn out. Can be fixed by replacing the commutator and brushes (brass brush). One issue here is that when the motor is worn, the pump itself will have some wear as well. Haven't heard of anyone who have fixed the motor having a failed pump tho'. Yet.

2: Worn (hardened) seals on the piston. Fixed with a service kit. Cause of sticky pedal. The piston on these masters is a bit special, "double action"; one part for normal use and one part for when the booster fails. (Which gives you weak fronts only, no rears)

3: Leak between reservoir and master.
Another related problem is overfilling the reservoir, because of lack of understanding of the system and not reading instructions on the lid (level check after releasing all pressure from booster accumulator). Brake fluid on the power connection to the booster motor make the bolts corrode and you loose the power. Brake fluid can also get into the motor, which will not do it any good.

You can check the booster and maintain the master. You'll find forum threads on both.
Checking the booster includes checking the power cable connectors, 2 small bolts on the booster motor. When you take the whole master out for service (service kit available with new rubber parts for piston), you check the motor. Clean inside and check brushes, commutator and bearings. There's a drain hole at the bottom which is known to have become blocked and the motor filled up with "porridge". Also check running time from zero to full charge. If you dismantle and check the motor and pump every 2 years or 30 k miles, you are likely to catch any problem before it becomes serious.

To minimize risk of problems, use only t0yota brake fluid. It has the right composition for the seals and valves.

I suspect that there are only two major versions of this master/booster: With or without Atrac/trac (anti-spin/skid), where the Atrac version has 2 separate lines/pipes to the rear brakes. I put the master from my 2000 (collision damaged) cruiser into my 2004, as they both had only one line to the rear (no Atrac). The part number isn't quite the same, but no problem. It looks like all 100 series get this problem somewhere between 100k and 300 k miles. My original 2004 was not shot yet at 270 k km, but the motor getting a bit noisy, and the 2000 had only 140 k km.

I Opened up the motor of the brake booster from my MY 2004. The booster pump had been a bit noisy, so I expected the motor to be on it's way out. There was quite a bit of debris inside the motor, and on the drive between pump and motor, but otherwise it looked good. Not much wear on the commutator, and the brushes even had a bit left. The bearings had a tiny bit of play. The cruiser had done about 270 k km.
I took the motor to an Electric Motor Repair & Rewind shop. They looked it over and claimed it looked good. Only the fraying "cable" to one brush worried him. Even the bearings he said were OK. He didn't have the right type of brass brushes in stock, so he couldn't help me there.

Some pics:
Not exactly clean inside

After blowing away some dust, it looked much better:

So, I cleaned it up, changed the bearings and put it back together again. Then I'll do the master piston service before putting it back into service.
The front bearing (behind the brush holder) just pulls out through the brushes.
The brush holder itself seems to be difficult to remove as the leads to the terminals on the outside are welded to the copper/brass conductors of the brush holder. That also goes for the brushes, not that easy to change. My brushes are actually less than 50 % worn, so I'll just leave them in. The damage to one brush cable is on 1/7 of the square, so I'll just clean it up a bit. All the debris and products of corrosion, together with the frayed copper threads would have been enough to make it noisy. A bit of PM in there from time to time is probably a good way of extending the servicable life.
Bearings: (dimensions in mm) (iD, oD, width)
Front: 8 - 22 - 7, type NSK 608D10, plastic sealed (- it looks like)
Rear: 6 - 15 - 5, type NMB R-1560KK, metal sealed both sides.

 

[StarCruiser]

Nice write up Uhu. I think Robson and Francis are doing quite a few of these now.

I’m assuming this is, essentially, just a vacuum pump? If so I can’t imagine why they’ve gone away from engine driven ones, except maybe for fuel efficiency?

 

[uHu]

It's the opposite of vacuum - a high pressure oil pump, storing the pressure in a nitrogen accumulator.
Good thing with electric is that you have full pressure without the engine running.

 

[StarCruiser]

It's the opposite of vacuum - a high pressure oil pump, storing the pressure in a nitrogen accumulator.
Good thing with electric is that you have full pressure without the engine running.

Sounds like part of the ABS system. Or is it just power assist to the brakes generally?

 

[BobMurphy]

When mine failed it was the brass connectors on the motor that fractured where they enter the motor. Quite bizarre really as I don't see where they can flex unless the plastic insulator mount is also a shock absorber:




As it came back from Robson & Francis Rewinds:




A close-up of the new, stronger contacts:



The whole sorry assembly - overkill or what ??



Bob.

 

[Iwan]

This is the most shocking appalling device I've seen to date on a cruiser.. has anyone fitted the dual brake booster off an 80 on the 100? Haven't seen the mount for the bulk head, but this is another reason to stick with the older cruisers IMO.. Newer motor's are a bit too smart and they dont cut it on longevity..

 

[BobMurphy]

This is what the mounting on the '100' looks like:



And, I think the ABS Gremlins live in here . . .



Bob.

 

[Iwan]

Thanks for the pics Bob! The first one looks promising and the second one concludes the idea LOL!

 

[StarCruiser]

It seems like this should be a service item at a certain mileage, though by the looks of it this could happen at a variety of mileages. I wonder if Robson and Francis would do a service exchange to swap these out before brake failure occurs? I’ll have a chat with Mike on this when I see him.