LX470 - Stalling during braking

[saxman2u]

Our 2001 LX 470 has been at the mechanic. We are the original owners so trying to figure this out. While it was having some work performed, it developed a new problem: the truck will stall when the brakes are applied, brake pedal pressed. This happens when in motion and braking or just at a standstill. This problem did not exist before taking it to the mechanic. The fan clutch bracket was making a loud noise so we had this repaired, this was the initial reason for taking it to the mechanic: loud noise from fan area while idling. While at the mechanic, we also had a new OEM radiator put in and cam seals were replaced as well. Since getting this engine work fixed, the truck runs fine. No codes are being thrown and no lights on the dash. With this new problem, it was suggested by the mechanic that the brake booster was pulling too much power/juice, and that the alternator/battery could not deliver enough power, so the aftermarket alternator and older battery were replaced with OEM alternator and battery. After this, the problem still exists. Now they want to replace the brake booster which is starting to get pricey. Trying to solve this myself, I asked them to remove the ABS fuse and also unplug the brake actuator to see if they could reproduce the problem. When they do this, the car runs fine and does not stall. So, my question is, is this a problem with the brake booster or did a wire get nicked somewhere or is pinched which is causing a short when the brake pedal is pressed? I don't want to install a new brake booster and still have the same problem.

Thanks for your help.

 

[getco]

LX470 Dies Intermittently After Timing Belt [Solved]

forum.ih8mud.com

Check the cam sensor wire and make sure it’s not rubbing on the belt. Since you said it happens when the car is not moving it doesn’t really make sense as the source of the issue, but I would try and rule it out anyway.

 

[Mchodl]

It sounds like a pinched wire to me. The theory about the booster pulling enough current to kill the engine sounds like a wild shot in the dark. In addition, the booster motor cycles on at startup to pressurize the brake system. If the pump pulling enough current to kill the engine was even possible, you would have a dead engine even without pushing the brake pedal.

 

[Mike NXP]

What did you find out with this issue? I think the mechanic needs to check over their work, if it didn't happen before you brought it to them. Sometimes we like to blame mechanics for other random problems after it leaves the shop but this seems too major to have just coincidentally started after they did the t belt job.

 

[saxman2u]

It was the booster. The mechanic swapped out a booster with another working booster and truck ran. Should get it back next week.