brakes failed couple times

[crazykiwi]

Hi guys new to 4wds took it for a quick drive to the river today crossing shelow water and playing in some mud afterwards droves for a bit in the dry then headed home hit the highway went to slow down to turn off and my brakes failed they came back to life after I stopped and pumped them a bit so took it easy and they was working fine again got into town stopped at diary then went home came round the corner to my street and my breaks went soft again for a short period this time
I know after being in a river it's good to pump the brakes a bit but I had used my brakes a bit before they failed what should I do? Or have done

Cheers only my 2nd day owning a 4wd it's a 96 isuzu wizard

[mudlva]

You need to detail how they failed.
Pedal to the floor. Hard pedal but no action. Etc

[crazykiwi]

Pedal went straight to the floor and there was no friction at all had to pull handbrake to slow us down

[mudlva]

sounds like master cylinder,
im sure others should start giving their views

[crazykiwi]

Second time it wasnt as bad pedal went to floor but only had to pump once to get brakes back but that was a good 30 min after the first time it happened

[crazykiwi]

Ok thanks mudlva at least I know where to start now

[ClassicCruiserSpares]

Have you checked the fluid levels since this has happened? any leaks from the system?

[crazykiwi]

yes was the first thing I done was check fluids all at good levels and doesn't appear to be any leaks it happened once today again started truck reversed out of drive and pedal went to floor only for one pump

[mudlva]

personnally i would stop driving it till its sorted keeps coming back to master cylinder best i can think of

question when driving with foot on the pedal do you get a vibration coming back to you just wondering if you have warped the discs and on first pump you are pushing the caliper piston out to just about grabbing and section push the piston is now starting to work, this is even worse with worn pads and discs combonation.

would explain them bring good before the river playday and why its started after that. if the discs were hotas and driving straight into the water they could of easily buckled, especially if worn.

[crazykiwi]

yea good thinking mudlva no I don't get any vibration I have only just bought the truck and the brakes had been done for its last wof 2 weeks ago I had stoped to let the dog out and was driving on the river bed before I went into the water but that is something ill remember is not go straight into water for that reason my mechanic friend also said the master cylinder so I think it will pay to get it in for a look over and a full service as I found today I had a broken cv joint

[3VILC]

Let us know how you get on, bit of a strange one that its fine sometimes then to the floor on others.

[Team Tonka]

Check the wheel bearings. Loose bearings let the disc wobble and push the caliper back.

[mudlva]

[3VILC]

I've found it more runs the disc on the edges of the pads as the disc is at an angle. Brakes are average and it chews the discs up but never really noticed a huge change in pedal travel? Just tweaked the terrano bearings up today as they were getting a bit loose. And discovered huge play in the drivers side of the bush truck when changing wheels on the weekend, at least I'm hoping its the wheel bearings, don't fancy doing a kingpin

[crazykiwi]

Haven't had a chance to look at it yet but it hasn't done it since I pulled out the broke cv wondering if that was hitting a brake Line while it was flopping around when I was driving it or something either way gonna give the truck a good looking over this weekend and see if I can find any leaks or anything