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I see that some of you with late build 99's have been able to do this as a bolt on. My 99 is newer than the cuttoff vin. For those who've done it - is it literally just unbolting the old MC and dropping in the new 997 MC? No new newer 996/996 booster required? This is on my spec boxster.
997
Thanks!
In my case, it was a simple uninstall and install the new 997 GT3 MC.
I realize this is the 996 forum and there are no 1997/1998 996's but since the OP referenced 986 Boxsters and this thread was helpful for this swap (legal for Spec Boxster racing class) I am replying here.
I did this installation today on my Spec Boxster race car which is a 1997 chassis. Some important notes on the install I came across.
1997 cars have a different pedal cluster than 1998 and 1999 cars. If you look at the Porsche parts manual you will see that there is a separate diagram page for the 1997 pedal cluster vs the 1998-1999 pedal cluster. The brake pedal on the 1997 is different such that the updated bolt-type pin on the updated brake push rod will not fit. Additionally the brake and clutch pedal shaft and bushings are all different on the 1998-1999 cars so swapping out the pedal for a later version on a 1997 may not be a direct swap. Given that the pedal mountings are a welded part of the body, and the pedal shaft is shared w/ the clutch and has several different parts of different design...not to mention it's all in an area that is very difficult to access, especially in my car w/ a full cage...I chose not to risk buying a bunch of parts to try to swap the brake pedal to the 98-99 style, and risk finding that it would not work. So I figured out how to modify the 1997 push rod to work with the updated/later design...as it turns out they are not that different.
Looking at the two pedal push rods, the 1997 version and the later/updated version the difference is the 1997 version uses a smaller hole at the brake pedal end with a pin and clip instead of a bolt. It has a spring centering piece also that the later/updated version does not have. Other than this and the "fins" on the forward end for holding the old style rubber boot, the 1997 version and the Updated version are identical in pretty much all dimensions. To avoid too much brain damage I ground off the "fins" with my angle grinder and did the installation using an OEM Porsche GT3 brake booster and the new style boot and connecting piece which all bolted up perfectly. The later style "connecting piece" that bolts the brake booster to the pushrod (eliminating the earlier clip style connection) fits perfectly w/ the original 1997 pushrod. You could probably skip grinding off the "fins" but if the angle is not perfectly straight on the push rod it appears that it could catch on the edge of the newer style plastic boot retainer that goes through to the passenger compartment, this could prevent the brake pedal from returning back to rest position.
It's also worth mentioning the "connecting piece" and locknut comes already installed on the new brake booster and is set at 138mm as recommended by the Porsche TSB. I would recommend measuring to be sure it was set correctly at the factory but mine was set spot on.
Needless to say modifying a brake part is something you should do at your own risk, so while I am sharing the knowledge here I cannot take any responsibility for others who may chose to try this solution, do this at your own risk.
A couple of other notes on parts: Firewall seal update set: 000 043 204 66 - Several parts in here are duplicate as they come together already installed on the new brake booster, however it appears you cannot buy them individually so just get this kit and be aware there will be duplicate parts. Updated brake push rod: 996 423 165 05 - Not needed if you have a 1997 car as you will have to modify the existing pushrod as noted above. Should fit 1998/1999 cars as they went to the later style brake pedal for 1998 (indicated in the Porsche parts catalog) Threaded bushing: 996 423 307 00 - Not needed for a 1997 car unless you replace the brake/clutch pedal cluster (Which may or may not be possible). Pin: 996 423 308 00 - Not needed for a 1997 car unless you update the brake/clutch pedal cluster (Which may or may not be possible).
12-15-2021, 02:05 PM
