Bleeding / Flushing Spongy GU Brakes...

[RoldIT]

Didn't want to hijack the Slotted Rotors thread.

My brakes are sprongy as a bag of warm squid. The brakes are always there but I don't get any positive feel back through the pedal until I pump it at least once. At first I thought they might be dodgy rotors or pads but after pumping them that doesn't seem correct.

I admit I haven't tried bleeding them yet but I was hoping to do a full fluid flush/replacement right through the lines but am not sure how to do it.

Do I just pump heaps of fluid through, doing each wheel one after the other or flush it with just air first till no more fluid comes out or what?

Do anyone else have this same issue with their GU?

Could this be a master cylinder or booster prob?

If I pump and hold pressure, the pedal will slowly go to the floor.

Is this a patrol "feature" or does this sound all wrong?

Cheers,
Kris

[ozy1]

well, to flush the lines through, id get your self one of the "power Bleeders" you hook them up to your air compressor, thats if you have one, then suck all the fluid through, from the left rear calliper, then make your way to the rest of your calipers,

then refil your system, and once again, bleed left rear, right rear, left front, right front,

i believe you start with the further most calliper from the master cylinder,

as for the spongy breaks, i believe its a Factory GU item, old man had the same prob, break place said its a common problem, they sused it out, as we bled the breaks and couldnt get it any better, you may finds its just the factory crap they use

[Ingenious-Eng]

Do not ever suck out/blow out/drain out etc. the brake fluid allowing air to enter the system because you will never be able to bleed out the air trapped in the master cylinder, if you get air in the master cylinder it will have to be removed from vehicle and bled whilst tilting it at two angles and pumping the piston whilst your fingers are blocking all ports and all the time maintaining brake fluid in the reservoir. Unless this is your idea of a good time that is!!!
Cheers.

[RoldIT]

Do not ever suck out/blow out/drain out etc. the brake fluid allowing air to enter the system because you will never be able to bleed out the air trapped in the master cylinder, if you get air in the master cylinder it will have to be removed from vehicle and bled whilst tilting it at two angles and pumping the piston whilst your fingers are blocking all ports and all the time maintaining brake fluid in the reservoir. Unless this is your idea of a good time that is!!!
Cheers.

Errr ... no, that doesn't sound like much fun.

I think I'll head over to a brake joint at lunch and see what they have to say.

Cheers,
Kris

[patrolmad]

Very common GU problem. I have been told it is because the rubber brake lines near the calipers expend whilst under pressure.

[Area54]

Brakes are not something that you want to be mucking around with - if you have to ask about procedures you have no knowledge about, it might be a job best left to the experts.

Nissan can hook up your brakes to their test machines to see if you have any line pressure failures, proportioning valve balance - loaded and unloaded, master and booster etc. A roller test will also test the effectiveness of the pads/rotors.

Do you have ABS?

The design of the system leads to having a spongy pedal feel, but unless you have some hard evidence and specs, you have nothing to go by other than a comparison to another vehicle.

[RoldIT]

I have just had my brake fluid system flushed and replaced with new fluid. It has gained some feedback in the pedal and feels somewhat better but I still have to lay the boot in to get any real bite.

I need to replace the brake lines with longer one anyway before I replace my shocks (as part of my ongoing suspension upgrade) so braided lines will be the next step. I will also investgate the flexible lines near the calipers.

If none of that works, the pads will be the next step (as they currently have heaps left and may not need replacing)

Ultimately, you all may be correct and this is just a GU trait that I will have to deal with. If so, I'll get over it.


BTW, No ABS, it's a Coil Cab. I have a Pajero before with ABS that makes these brakes look like "Flintstone" brakes.

[toughnut]

I just replaced my brake pads with race brake brand pads.

UNFUGGINBELIEVABLE

Made a massive difference. They cost me about $200 for the lot but worth every cent. Next step is braded brake lines and slotted rotors. The lines are legal now.

[RoldIT]

Sorry, not real clear on what you installed.

Are they a race "spec" pad or is "Race" the brand name?

Where did you obtain them from?

Cheers,
Kris

[toughnut]

The brand is Race Brakes disc brake pads. They are Australian made and owned as well. Couldn't believe the difference they made. It cost about $80 for the rear set and $120 for the front set. But as I said stops like a small car. I put my foot on the brake about the same as I usually would and was pushed forward into the seat belt. Massive difference. That's on standard rotors as well. Peddal feel was better mainly because I didn't have to push as hard on the peddal to get the same results so I felt like I had more control. I was able to balance the braking so that the tyres were just starting to chirp a bit. Braking distance was greatly reduced but I now have to make sure I don't have crap lieing around in the cab

[toughnut]

Whoops. I got them from brake mart here in Townsville but most brake speciallist places should be able to get them.
The part numbers are:

DB1361 RB74 front

DB1148 RB24 rear

[RoldIT]

Cheers, for $200 is sounds like it'd worth it.

I have a hunt round down here.

[rlaxton]

Cheers, for $200 is sounds like it'd worth it.

I have a hunt round down here.

You won't have to hunt far. Race Brakes themselves are in North Melbourne near where the freeway crosses Racecourse Road.

44-68 Racecourse Rd North Melbourne (03) 9326 6088

They do pretty reasonable work but not all of their pads are perfect. I had RB38s on my MY02 WRX STi and had them catch fire when driving hard down the Reefton Spur. This was a combination of dodgy compound and their use of a smaller die than the original Brembo pads. For Patrols they probably use the correct sized die to make a pad exactly the same size as the OEM unit.

Richard.

[RoldIT]

Cheers, for $200 is sounds like it'd worth it.

I have a hunt round down here.

You won't have to hunt far. Race Brakes themselves are in North Melbourne near where the freeway crosses Racecourse Road.

44-68 Racecourse Rd North Melbourne (03) 9326 6088

They do pretty reasonable work but not all of their pads are perfect. I had RB38s on my MY02 WRX STi and had them catch fire when driving hard down the Reefton Spur. This was a combination of dodgy compound and their use of a smaller die than the original Brembo pads. For Patrols they probably use the correct sized die to make a pad exactly the same size as the OEM unit.

Richard.

Cheers mate, good to know.

Can't say I've heard of them before but also never really needed to chase down pad upgrades in the past either.