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Brake booster part number

Old 01-13-2019, 08:20 PM
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Default Brake booster part number

I recently purchased a 924 base which was stored in someoneís backyard for a very long time with the hopes of restoring it. Itís been difficult but fun and now I understand why a car should never be undriven.

The current hangup is the brakes. Most components have been replaced or rebuilt but the car still hardly stops. The pedal goes to the floor with limited stopping power. Iím currently attempting to locate the vacuum lines related to the brake booster.

However, the part number on the brake booster doesnít match the number in my parts catalog or any of the Porsche auto parts stores. The correct part number for my for my 924 (4 lug, non sport option) appears to be 477 612 107G. My brake booster has the blue VW/Audi sticker on it with part number 477 611 907D. Could this be a European brake booster? Is it the same part? Or could it be related to my braking problem?
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Old 01-21-2019, 03:17 PM
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Old 01-21-2019, 04:10 PM
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Thank you. That parts list seems to confirm that I have a brake booster with a different number.

I now realize that I forgot to mention that this is a 1980 model. However, the brake booster number appears to be identical to the 76-79 part. I find it interesting that the different letter at the end of the number sequence refers to a brand of booster. Could it be that a particular master cylinder needs to be matched up with the same booster? Or am I overthinking this? Nonetheless, Iím still curious where my odd brake booster came from and if it is, or will be the cause of poor braking performance.

I have also been set straight that the symptoms Iím experiencing are consistent with air in the system or the rear brakes being out of adjustment. Since I believed I had both of those issues under control, I decided it might be a booster issue.

Ill be bleeding (yet again) and adjusting again to try and get it right. If Iím lucky, Iíll get it right and the weird booster will work (maybe itís a European part).

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