help needed on Prado 120 brakes

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Dingo
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Tue May 03, 2016 8:19 am

Hi Fellow Prado owners

I have a small issue with the brakes on my Prado 120, I'm going thru rear brake pads twice as fast as the fronts. I'm getting approx. 10 000 kms on a set of rears and have now changed the pads twice without replacing fronts - now I know it should be the other way around.

The vehicle went for a service at Toyota and they checked the braking system and changed the brake fluid, etc and couldn't find anything wrong. Prior to that I sent the vehicle to a Brake place and they checked the calipers etc, clean them up and found no leaks etc.

Under hard braking you can hear the rear tyres squealing, which tells me that the fronts are not braking correctly and all the braking is happening on the rear.

Has anyone else experienced this?? can anyone refer me to a brake specialist to assist.

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jacques kotze
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Tue May 03, 2016 12:06 pm

My prado doesn't have any issues like that, no idea what or why...sorry.

Nick (Nexus)
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Tue May 03, 2016 12:14 pm

Hello Scott

Also can't say I have had this issue.
Sorry, hope you come right there.

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Knuppel
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Tue May 03, 2016 1:32 pm

Does your Prado have a load sensing valve on the rear diff?

It is a rod that is connected to the diff and to a valve on the side of the chassis.
It reacts to load. The heavier you load the vehicle the more brake pressure it allows to the rear brakes. It could be stuck or have been set up wrong or been disabled.

Have you owned the vehicle since new or did you buy second hand?

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Dingo
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Wed May 04, 2016 9:57 am

Thanx Guys

Spoke to Toyota this morning and I'm taking the Prado in, they can apparently measure the brake pressure. One of the questions is the load sensor and they'll check that too.

I'll keep you posted.

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Dingo
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Thu May 12, 2016 7:47 am

Feedback for those interested:

Vehicle spent 3 days at Toyota while they ran a few checks and waited for some parts.

The actuator, ABS system and wheel speeds were checked on the computer - All were good.

on visual checks it was found that the rear calipers weren't releasing correctly and it was recommended to replace the seals - caliper kit replacement. This made sense with the abnormal rear pad wear.

It still didn't answer as to why the vehicle was braking more to the rear, especially under hardish braking.

Decided to do the seal kit replacement on the fronts aswell. When the technician opened up the front calipers he found the seals very hard and the pistons were all fouled up and sticky.

New seals fitted and pistons polished and the braking dynamics of the vehicle is completely different.

The reasonable thinking on this is that the front pistons were sticking on applying brakes, which gave the actuator a false pressure reading and it distributed the pressure towards to back for balanced braking. the rear calipers were sticking the other way round and not allowing the piston to retract correctly - kinda makes sense to me, even more so now that the vehicle is braking correctly.

Nick (Nexus)
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Thu May 12, 2016 1:36 pm

Thank you for the feedback, though it may take a few read throughs to understand that.
Guys like me are not that clued up on the technical side.

Appreciate the expertise and glad to hear you came right.

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Knuppel
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Thu May 12, 2016 6:08 pm

Thanks for sharing Scott, it makes sense. And so I also learn.
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ChrisF
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Thu May 12, 2016 7:37 pm

Scot glad it is sorted.


In the 80's I had a 1275 Mini. Time came to replace the rubbers on one of the slave cylinders. Old mechanic recommended that I do the FULL system while at it. The way he explained it was basically that working on one wheel only can cause issues at the other wheels - very much like what you have just described. Seems that old mechanic gave me good advise. :)

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