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2.8 rodeo strange brake issues

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2.8 rodeo strange brake issues

Postby magicdeo » Mon Jan 27, 2020 9:22 am

Gday everyone. I have a 1997 2.8 dual cab 4x4 rodeo with a strange brake fault. The brakes are average but I get used to them and dont think much of it, but every now and then, maybe once every 1 or 2 months, the brakes work fantastic for about 2 or 3 minutes after starting the vehicle before going back to their average selves. Can anyone explain this? Very intermittent and it never happens while im driving, it only ever happens straight after i have started the car after sitting for hours and strangely enough, 9 times out of 10 it will be when the weather is a bit wet. I certainly know when it does this as the brakes are brilliant, i dont have to brake hard, i notice the difference just reversing out of my driveway and like I said, 2 or 3 minutes later they are back to average for another month or so. Any ideas?
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Re: 2.8 rodeo strange brake issues

Postby isuzurob » Mon Jan 27, 2020 6:06 pm

Aftermarket alternator? The vaccum pumps dont seem to be anywhere near as good as the genuine pumps, had same issue in my rodeo and bighorn, also handbrake light use to flash when pressing the brake pedal, fitted a genuine alternator again and all worked as it should, that was my case anyway
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Re: 2.8 rodeo strange brake issues

Postby geeves » Tue Jan 28, 2020 2:18 pm

Just a thought. You notice brakes a lot better after starting and esspecially backwards plus when wet. I wonder are the pads absorbing moisture making them grabby?
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 2.8 rodeo strange brake issues

Postby magicdeo » Wed Jan 29, 2020 5:21 am

Are the vacuum pumps replacable or are they a complete unit with the altenator? As far as i know it is the genuine altenator. In saying that the ute has 485k on it so possibly a worn vacuum pump? Not sure why it would work sometimes though but possible i guess? Do you know how the brakes would feel without vacuum? Would they still be ok or basically non existent?
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Re: 2.8 rodeo strange brake issues

Postby magicdeo » Wed Jan 29, 2020 5:22 am

geeves wrote:Just a thought. You notice brakes a lot better after starting and esspecially backwards plus when wet. I wonder are the pads absorbing moisture making them grabby?

I dont think this would be the case geeves as there is noticable difference in feel from the brake pedal aswell. Sort of hard to explain but its not just the brake performance which changes its the feel of the pedal also
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Re: 2.8 rodeo strange brake issues

Postby geeves » Wed Jan 29, 2020 1:44 pm

Right. Is the peddle normally very hard but softens when they work better? Does your brake warning light ever come on? This is the same light as the handbrake. Does it have drums of disks on the back?
I would of expected vac issues to cause the light to come on.
Siezed caliper slides might cause this. Take the front calipers off and make sure both slides in the mounts are free moving. Same in the back if its disk
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 2.8 rodeo strange brake issues

Postby turnturn » Wed Jan 29, 2020 6:39 pm

Can you fit a vacuum gauge somewhere to see if the vacuum is different under good and bad braking conditions?

Oh, and the brakes are horrible when there is absolutely no vacuum.
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Re: 2.8 rodeo strange brake issues

Postby magicdeo » Thu Jan 30, 2020 5:18 am

It has drum brakes on the rear. I have checked the caliper slides 2 weeks ago and they were free. The pedal is certainly alot firmer when the brakes are worse but the brake light has never come on. Good idea might be worth tyring a vacuum gauge on there
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Re: 2.8 rodeo strange brake issues

Postby geeves » Thu Jan 30, 2020 1:16 pm

Does that light come on when applying the handbrake? Also check the sensor on the brake servo isnt unplugged
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 2.8 rodeo strange brake issues

Postby turnturn » Thu Jan 30, 2020 5:43 pm

Or the brake vacuum booster unit is failing? I don't know if these fail gradually or not though.
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Re: 2.8 rodeo strange brake issues

Postby magicdeo » Fri Jan 31, 2020 8:11 am

Yep light comes on with the handbrake. If things were failing i just cant work out why every so often it works perfect. Could it be the rear proportioning valve? When they do work really well never coincides with different loads on the ute but maybe something in that unit is causing it?
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Re: 2.8 rodeo strange brake issues

Postby geeves » Fri Jan 31, 2020 2:29 pm

Try getting a non return valve from a petrol car at the wreckers and fitting it in the vac line as close as you can to the servo
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 2.8 rodeo strange brake issues

Postby magicdeo » Wed Feb 05, 2020 11:34 am

Do the diesels not have one?
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Re: 2.8 rodeo strange brake issues

Postby geeves » Wed Feb 05, 2020 1:46 pm

There is suposed to be one inside the booster but generally it shouldnt be required in a diesel as its a sealed system unless there is a leak. My wizard had a leak somewhere I couldnt find which meant bad brakes for up to 30 seconds after starting but the non return valve fixed it.
Sanding your knuckles before starting work can help. That way you cant skin them
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