Succesful 406 HDI brake booster replacement
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  1. #1
    Join Date
    Nov 2011

    Default Succesful 406 HDI brake booster replacement

    I'm not always successful searching, but i couldn't find any documented how to for brake booster replacement, so i thought i would do my bit and write down how i went about it. Wasn't as painful as i thought and was about 30 mins work to remove and then again going back in. I had read via here or other forums that my symptoms of harder feeling brake pedal, sinking feeling when holding it on and worst of all serious loss in power, did in fact prove to be the rear seal of the brake booster. I had read some banter as to it being this or that, faulty pump etc - I just removed the vac line off the booster and plugged it. Car went like a rocket again so made sense to me that was the problem ie. loss of vacuum to suck on the turbo wastegate ( I think that is what it is). Also made pedal go very hard but brakes operating perfectly well if standing on pedal.

    As soon as I had it out it was clear that the rear seal was damaged and had popped out of the booster. These boosters are no longer available new and 'not repairable' although after talking to Carl at Power Brakes in Gilles Plains (Adelaide), he said that this ATE booster is actually not bad and up to normal ATE standards.... except that rear seal that they got wrong and 90+% of what they see is just that rear seal and they can repair that. Cost me about $150 to test and repair and all good now. My only option I could find was a used one from a wrecker at Gepps Cross for $300 and I would much rather a brand new seal (which is the usual problem) at half the price. Power Brakes I believe are happy to send stuff Australia wide. And you can ring them with your exact model/vin and they can check for you that it is that booster that they can repair. I was told by a reliable source to specifically ask for Carl because others may try and to tell you it can't be repaired.

    Anyway this is how i did it on a 2002 406 HDI,

    1. Unclip the big wiring loom that is just above the booster and pull it forward so you can get access to the nuts behind the booster. I also undid the bracket just in front of it holding the electrical thing with the red rubber cap on it – two nuts with a 10mm spanner and it just buys a bit more room
    2. I used a 13mm ratcheting ring spanner, mine has a swivelling head but a normal one might fit too – remove the two upper nuts holding the booster to the bracket.
    3. Remove the rubber bung that goes to the vacuum pump.
    4. Undo the two nuts holding the master cylinder and pull that forward
    5. I then jacked up and removed the front left wheel and removed the rear part of the guard lining. Those clips you just push in the middle bit and then pull them out – to put back you push the inner pin back so it sticks out and you can put them back and push back flush to hold. If your hands are small enough you can get in through the two holes in the guard inner, but removing the guard inner just buys a bit more room and while you are at it you can clean out leaves and mud behind it.
    6. And don't forget a jack stand if you have the wheel off!
    7. Through one of the holes you can flick off a plastic cap that is on the bottom of the booster bracket.
    8. Next I removed the circlip on the pin that goes through the booster shaft. You can't see it but if you feel around with your finger you will feel an open side and a flat side and you just pull (or push) and it will pop off. See photo for the shape you are feeling for. It it tight and it may help to have someone push on the brake pedal to bring it forward more.
    9. Push up now on the bottom of the pin – I couldn't pop it out so I then went to the top to pull it up, but it hits the firewall.
    10. So next I got my ratcheting 13mm ring spanner and undid the bottom two bolts. I could reach in from the wheel well from under the chassis and then look through the side hole for guidance.
    11. Now you can pull back on the booster and I got someone inside the car to gently push on the brake pedal while you pull up on the pin that attaches the shaft of the booster. Hope that makes sense but by moving it away from the firewall so you can pull it up without hitting the angled firewall and also without load on it is what you are aiming for.
    12. I didn't want to re-bleed my brakes but if you are happy to do that you could probably just remove the master cylinder and it would make it all easier. I removed the plastic brake pipe spacer and was getting close to pulling it up enough to be able to slide out the booster, but then decided just to pull out the pipe from the reservoir to the clutch master. I put a rag under it quickly put my finger over ends and my son pulled out the booster. I then plugged it back together. Same process on replacement and while I considered I may need to bleed clutch, it all worked perfectly. I guess there is enough fluid in the line and then any air has floated back to the reservoir, all being before the pressurised part of the clutch system.

    Succesful 406 HDI brake booster replacement-dscn2105.jpgSuccesful 406 HDI brake booster replacement-dscn2106.jpg

    Putting it all back was pretty much a reversal of taking it out. Main point is to have someone push on the brake pedal to help get that pin in the booster rod and getting it all lined up. Then once the pin is through, I found it easier with the brake pressed to get the clip back on – a bit fiddly though. All the rest was pretty straight forward. I added a photo of the clip (bit blurry focus) – might help to see what you are trying to deal with when you can't see it. I also remembered the old trick when you are trying to do something you can't see, close your eyes - it really does make it easier to feel what you are doing. Its a straight slide off push on thing though.


    Hope that helps someone and hope it makes sense!
    Last edited by craigb; 2nd January 2018 at 11:18 PM.

  2. #2
    1000+ Posts N5GTi6's Avatar
    Join Date
    Mar 2004


    The reason I always treat "it can't be done" as more of a challenge than a valid response. Aren't ratcheting ring spanners fantastic ? ! While I don't use them for tightening, they're great for rapid movement of nuts and bolts in situations of difficult access.

    Thanks for the update and the info.


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