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The bracket was added to all WP's from 87 onwards to ensure the pivot bolt does not bend.
That is the basic difference between an early WP (77 to 86) and the later WP's (87 to 95).
Many have retrofitted this setup to earlier cars - mostly 85/86 S3 32v.
Porsche increased the size of the pivot bolt in iterations 77 to 86 but the opportunity to bend the pivot bolt was always there. The added bracket put "paid" to that problem.
Note: If you are using a PKT the bracket is no longer of any use. Hence the reason why you can use either an early or late WP with a PKT.
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Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Rebuilding '90 GT OEM tensioner (PO mechanic didn't do it with timing belt change 4 months ago). Boot was totally gone. The tiny flat head bolt that goes into the idler shaft on the water pump was loose when I removed it. I have not recalled the bracket that runs from the top of the water pump to the idler on any of my other 928's with Laso pumps. After checking & cleaning the parts, I tightened the tiny bolt and now the tensioner pulley assembly will not move. If I back it off, it move freely. What am I doing wrong? Something defective? It is a GMB new pump (not my choice).
The bracket was added in 1987...and needs to be there. The bracket modifies the pivot bolt from single shear to double shear greatly increasing the strength and stability.
No washers, no spacers. The bracket attaches directly onto the end of that shaft screwed into the water pump with the screw you have. If you add or need a spacer to make it function, the bearing on the arm will not contact the belt correctly, fore and aft.
The dimension of the shaft should be slightly larger than the distance between the two plastic bushings in the idler arm, for this to pivot. Check this with a pair of calipers.
The only possible thing that can be wrong, if the shaft and the arm have not been altered, is that the two bushings could be incorrect or not pushed in enough. I install new bushings at every belt change. If you don't know their history, you should buy new ones and install them.
The bracket was added in 1987...and needs to be there. The bracket modifies the pivot bolt from single shear to double shear greatly increasing the strength and stability.
No washers, no spacers. The bracket attaches directly onto the end of that shaft screwed into the water pump with the screw you have. If you add or need a spacer to make it function, the bearing on the arm will not contact the belt correctly, fore and aft.
The dimension of the shaft should be slightly larger than the distance between the two plastic bushings in the idler arm, for this to pivot. Check this with a pair of calipers.
The only possible thing that can be wrong, if the shaft and the arm have not been altered, is that the two bushings could be incorrect or not pushed in enough. I install new bushings at every belt change. If you don't know their history, you should buy new ones and install them.
Great clarification Roger & Greg. That explains the mystery. The bushings have not been changed. I will start there to try to eliminate the 2 washers I have installed. Roger, add those bushings to my order if they have not been shipped!
05-28-2017, 12:27 PM
George Layton March 2014
). Boot was totally gone. The tiny flat head bolt that goes into the idler shaft on the water pump was loose when I removed it. I have not recalled the bracket that runs from the top of the water pump to the idler on any of my other 928's with Laso pumps. After checking & cleaning the parts, I tightened the tiny bolt and now the tensioner pulley assembly will not move. If I back it off, it move freely. What am I doing wrong? Something defective? It is a GMB new pump (not my choice).
