Brake issue NP MY04 with ABS, possible master cyl??

[Bisho]

Hi guys, needing some help.

I have searched the forum for possible answers and am aware of the recall on NMs and early NPs with brake issues regarding master cylinders and accumulators.

I am hoping this is not my issue as it is a later build than those recalled (recall was vehicles up to July 2003, mine is Oct 2003) and seems to have different symptoms.

I noticed a few weeks ago when at the lights my brake pedal would slowly collapse. The pressure seemed to reduce under my foot.

It would happen semi regularly, now it happens every time and the pedal goes to within an inch of the floor No lights come up on the dash. The brakes are not fading, just running away from under my foot!

I took it to the service centre and they could not diagnose anything. Just bled the brakes and they said it was fine, which it was for 5 minutes driving it home. The problem was still there.

Second visit to service centre they said it is the master cylinder and will source one. In the mean time I took it home.

4 days later they have gotten back to me saying they are having problems finding the part in stock anywhere and that they have spoken to the specialists and they are suggesting it is a vacuum pump issue...but they don't really know!

They are organising me to take it directly to the brake specialist or a Mitsubishi service centre next week to see what they diagnose.

Anybody have any ideas?

[DiDExceed]

I'd reccomend another service centre, if they knew what they were doing they would know the brakes are not boosted by vacuum on the NP pajero like most vehcile, yet and motor and accumulator, vacuum pump is not involved, HBB units are know to have problems however i wouldn't say it "common", probably not the issue, but there is an earth on the inner gaurd near the brake master unit, check it is clean and tight, i have had two now with HBB issues and it turned out to be a bad earth after a mitsubishi dealer had put a new HBB unit on and it not fixed the issue.

[Goodsy]

5000,7500,10000,15000?

edit. WTF was I on.

[Bisho]

Thanks Didexceed. I assume the earth is this spot here in the photo.

I have cleaned it all up but have the same problem.

Hey Goodsy, what are you on about? Is that meant to be the start of another thread?

[Bisho]

OK, more info.

Playing around with the brakes with the engine off and continual steady pressure on the pedal it will gradually collapse to the floor in about 10 seconds.

Turning the key to 'accessories', I can hear the hum of the electric motor on the HBB. It runs for about 4-5 seconds and stops. It will run for a few seconds most times when I apply the brakes and push the pedal to the floor and makes very little if any discernible difference to the pressure in the brake pedal.

With the engine running, it seems to have even less resistance. With a slow gradual stop, the pedal is on the floor BEFORE the car stops! A quick pump on the pedal to pull up that last bit fixes that.

A hard fast stop is no worries, the pedal will continue to the floor after the vehicle has stopped. ABS seems to be working with no worries.

Seems to be degenerating! 40 km away from the service centre!

[Bisho]

Well the warning lights on my dash (4 of them) came on with an audible alarm after I sat in the car and pumped the brakes vigorously while idling.

I have checked the fuse that gave Catchin Jack the same problem, my fuse is OK.

I will see if I can check all the relays relating to ABS, Off the top of my head I think there are 3.

[DiDExceed]

That's the one, worth a try cause it is free , sound like you may have an internal leak in the master the only place I know of that may repair them is BHSS in Brisbane, they do the Wabco units found on land/range rovers and a few other European makes which is a similar setup.

Was anything done to the vehicle mechanically or an accident that has led to the issue or it just happened one day?

[brianwanless]

If it was an earlier model with vacuum assistance, I would have said master cylinder for sure. Faulty main cup or damaged cylinder bore. It still may be that, but it is a job for the experts these days.
Do you have a Better Brakes or similar business near you, they would be the place to start. But sooner rather than later, as it could suddenly get worse and no amount of pumping will stop you.

[Bisho]

That's the one, worth a try cause it is free , sound like you may have an internal leak in the master the only place I know of that may repair them is BHSS in Brisbane, they do the Wabco units found on land/range rovers and a few other European makes which is a similar setup.

Was anything done to the vehicle mechanically or an accident that has led to the issue or it just happened one day?

I appreciate the input, I can rule one thing out at a time. Nothing has been done mechanically and there has been no accident.

If it was an earlier model with vacuum assistance, I would have said master cylinder for sure. Faulty main cup or damaged cylinder bore. It still may be that, but it is a job for the experts these days.
Do you have a Better Brakes or similar business near you, they would be the place to start. But sooner rather than later, as it could suddenly get worse and no amount of pumping will stop you.

Yeah for sure, we're not driving it. I am bound with the current service centre as my warranty is with them.

[jol]

My NM had a problem years ago, not sure if the NPs might be the same, where it had a hole in the diaphragm in the brake booster pressure accumulator. If you held the brake pedal on it would gradually leak pressure and go to the floor. Only the Mitsu service guys seemed to know about this and could replace it.

[Bisho]

I phoned BHSS the other day. Very helpful thanks DIDexceed. They said the Pajero is one of the more common HBBs they have to repair. They said it usually cost anywhere from $500-$1500. They really only like to repair them if they can also install them and drive the vehicle, understandably. Pity they are in Qld.

The Paj is going to a Mitsubishi Service Centre next week.

[Bisho]

To bring this saga to an end...

Ended up going to a local Mitsubishi service centre. They got a fault code indicating the HBB. (I could only get a fault code of the engine light flashing indicating no.16, which is the boost air temp system???)

Through further inspection they found the HBB to be internally leaking.

New replacement unit fitted - $2500
Used unit fitted - $1850

I took the used option, $300 labor, $1550 for the used part!!!!

Lucky I had my used car warranty cover the first $1000, so cost to me was $850. Much the same sort of cost if I had have sourced the part myself and got my local mechanic to fit.

The End.

[MTN-KAT]

This really is a sad saga. Bisho's vehicle is just 10 year old and already faced with an $1850 brake master cylinder repair, for a used item! One that already had failed!! My NL is 14 year old, same brake master cylinder and IF it ever needs repair will be only a fraction of the cost to Bisho. And the guru's call this progress? Progressing their profits, that's about all. A little while ago someone in another thread on this forum asked "are we being conned"? The answer is clearly a resounding YES.

[Ricstar]

Well my Paj is 11 years old, 127,000k and yep, I have the pedal sinking to the floor.
Sit with foot rested on it, after about 20 seconds sinks a bit and then stops, then after another 20 seconds continues to sink.

Stops fine, holds the vehicle. Can slam on brakes and paj pulls up and if hard enough ABS kicks in.

All other tests are ok, Accumulator working fine, ABS all good.

Always had fluid flushed every 2 years and only had rear pads replaced (2nd set on car since new) and rear disks machined on car 3 months ago and fronts done a year ago.

I have done all the right things.

I have read through all old threads about this issue last night and today, but just to make sure I have the latest, can anyone recommend someone in Bris who reconditions HBB's. and/or wrecker where I could consider sourcing a 2nd hand one or someone who can look after the whole issue for me and I don't have to sacrifice my first born or an arm or a leg.

I find it frustrating that these units are not simple enough to replace parts that would normally be expected to wear, specifically the master cylinder primary and secondary seals.

In the day you could go to Repco and get a master cylinder seal kit. Now my option from Mitsu is to buy a $3000 assembly.


Next we will have motors whereby you cant replace the spark plugs, but have to replace the whole thing for $12,000. Or when the tyres wear out at 70,000km you have to replace the whole wheel, hub and rotor as they are a one piece non serviceable item.

Sorry for being so sarcastic and disgruntled.

So hoping someone else can give me some new options to get this sorted in Bris.

Thanks

[Nab]

As a matter of interest, my last 2 Patrols brake pedals would sink to the floor after about 5-10secs pushing quite hard.

I know they are a different beast but maybe its not all bad news?