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HZJ105 brake system not holding pressure?

keenasmustard

New Member
Joined
Jul 12, 2021
Messages
3
Country Flag
australia
I have recently purchased an automatic HZJ105 Landcruiser with ABS and I am finding that the brake system is not maintaining pressure. The brakes generally work OK and bring the vehicle to a stop, but after a few seconds the pedal softens and the car begins to creep forward, requiring you to push the pedal further to stop it moving. If I'm stopped for a while I need to release and reapply the pedal to get pressure back.

There are no visible leaks on the brake system and the the fluid level in the reservoir has not gone down. I understand these vehicles run a hydraulic booster / ABS accumulator which is prone to problems, but there are no warning lights coming up on the dash and the accumulator motor is not making any strange noises. I also believe the accumulator and master cylinder come as a complete assembly from Toyota for about $3500 AU, but the accumulator motor can be rebuilt for about $200.

I am thinking that the problem may be an internal leak in the master cylinder. Keen to hear thoughts or opinions from anyone who has experienced similar issues. Thanks in advance.
 

Beastrider

Active Member
Joined
May 31, 2021
Messages
92
Country Flag
uk
Hi - If the pedal is going down, the fluid has to go somewhere. You say it’s braking ok but then the pedal creeps down. If there is no external leak, then it could be an internal leak inside the master cylinder. If so, the fluid will be bypassing the pressure seal and going back to the reservoir. When you release the pedal, the master cylinders takes back the ‘lost’ fluid and then the cycle repeats as you press the pedal again.
You might be able to see the reservoir fluid level rise as the pedal creeps to the floor although I think the reservoir on yours is quite wide - the level rise will be slight. You could try overfilling the reservoir so that any fluid rise is more obvious ( but be careful to avoid spilling it). Then bleed off the excess later through one of the caliper bleed screws. A level rise would at least confirm an internal m/cyl leak. Good luck.
 
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