915 rebuild and ITB/EFI project, here we go!

[Trackrash]

Originally Posted by evan9eleven

Thanks Peter! I'll check my manuals.

The engine stand and benchtop press arrived today; I'll have a go at degreasing the beast tomorrow evening so I can hopefully start the teardown this weekend. I've decided to open it up before ordering parts, even though I plan to replace most of the major bits.

Speaking of parts I've been advised that when it comes to synchros that the original Porsche items are the only way to go, but that with bearings the equivalent FAG and Timken units are just fine. The head scratching really starts when there are two different aftermarket bearings to pick from our host. Like the mainshaft bearing 999.052.030.00. Besides the $224 P original version, there are two from FAG. One at $116 and one at $58. I'm more then happy to settle for one of the less expensive two given the manufacturer, but what makes the difference between those?

It gets even more confusing when the manufacturer is just "OE Supplier" or "OEM" or "IR Torrington" or something else. If anyone can enlighten me here, I'm happy for any tips I can get.

There has been some recent discussion on dog teeth here. Need to replace dog teeth...
IMO most of the time, OE is good. Only difference is Porsche has not actually touched it. Read about dog teeth, however.

[al lkosmal]

Evan,
Good luck with the project. I know that there should be no shortage of frosty beverages in the man cave.

regards,
al

[evan9eleven]

Originally Posted by kevingross

On the ring-to-pinion backlash, again follow what the manual says to get it within the specified range. You need not buy the factory tools. For years I used a simple home-made equivalent, picture below, that in fact works better than the factory tool when re-using differential carrier bearings. (And then I bought the factory tool, because of course he who dies with the most factory tools wins.) There are lines drawn on the angle iron stock at the nominal radius at which to measure free-play.



Best of luck with the project, and keep smiling! Pete's wiki on 915 rebuild is fantastic and will see you through the project.

Kevin! Thats a mighty cool homemade backlash tool. Do you have more pictures, especially with it in use? I've ordered a dial gauge and am starting to get my head around the concept and procedure, but exact dial gauge placement and what variation of tool to make are still eluding me.

[Peter Zimmermann]

Evan; here you go...

915 – P259 tool measurement request… (With pics)

I know that you'll see it in my Tutorial, but don't skim past Post #45!

[evan9eleven]

Originally Posted by Trackrash

There has been some recent discussion on dog teeth here. Need to replace dog teeth...
IMO most of the time, OE is good. Only difference is Porsche has not actually touched it. Read about dog teeth, however.

Yup, I'm up to date. R&S finally got their shiznit together and added the backcut, so I'll get one of theirs for 1st gear. 2nd,3rd and 4th are brand new from Guard and include the dogs, so I'm good there. 5th gear worked just fine so I'll probably leave it alone, especially since our max speed limit here is 50mph and 5th is just for show.

Originally Posted by al lkosmal

Evan,
Good luck with the project. I know that there should be no shortage of frosty beverages in the man cave.

regards,
al

Thanks Al! No words have ever been written more true then these. Cheers!

Originally Posted by Peter Zimmermann

Evan; here you go...

915 – P259 tool measurement request… (With pics)

I know that you'll see it in my Tutorial, but don't skim past Post #45!

Thanks Peter! I've got that thread bookmarked.

[evan9eleven]

One step closer! Its not spotless but a whole lot cleaner then it was, now mounted on the stand and ready for dissassembly. Just waiting on an old clutch disc from a friend so I can make a P37a main shaft locking tool and I'll start tearing it down. Can't wait!

[Trackrash]

You don't need a locking tool for disassembly if you have an impact wrench. Just buzz off the two big nuts. You can either use a rag to jamb the gears or put it in two gears at once.
If you read this thread, he found a method to disassemble without loosening the shift forks on the rods.
http://www.pelicanparts.com/MotorCity/marcesq3/TrannyRebuild.htm

edit: corrected link

[evan9eleven]

Originally Posted by Trackrash

You don't need a locking tool for disassembly if you have an impact wrench. Just buzz off the two big nuts. You can either use a rag to jamb the gears or put it in two gears at once.
If you read this thread, he found a method to disassemble without loosening the shift forks on the rods.
file:///C:/Documents%20and%20Settings/Gordon/Desktop/Porsche/TrannyRebuild.htm

Thanks Gordon. I have two impact guns but only up to 24mm impact sockets. Thinking a standard socket probably has no business on an impact wrench.

I've seen Gordo and others reference not loosening the shift forks so I'll give that a go.

Your link didn't work btw.

[Trackrash]

Here is the thread I was linking to. Worth a read. Lot's of DIY info and short cuts.
TrannyRebuild

[Gordo2]

Originally Posted by evan9eleven

Thanks Gordon. I have two impact guns but only up to 24mm impact sockets. Thinking a standard socket probably has no business on an impact wrench.

I've seen Gordo and others reference not loosening the shift forks so I'll give that a go.

Your link didn't work btw.

Been watching your progress but not compelled to comment considering you're hearing from some very experienced experts on the board.

I locked the shafts using a clutch as a P37a. Started with bolted up configuration, but ended up welding something up something resembling the actual P37a. I found myself using it for a few steps during rebuild and decided to make it easier/faster to install & remove each time.

I used the clutch/lock and a regular socket (from local auto parts store) to remove the nuts with an air impact. The sockets were huge / heavy duty, so I wasn't concerned that it wasn't hardened impact socket material - I think if the socket did fail, it would just split the socket. Safety glasses are always a good idea working with impact wrenches…

Doing great - take your time and enjoy.

Gordo

[evan9eleven]

Obviously it was time to poop or get off the can, so I plowed through the first two parts of Peter's tutorial today!

No carnage, just worn syncros to see so far. First and second gear dogs are rounded off a bit but nowhere near what I was expecting.




Everything in order as instructed. Away down!
I took my own route here and removed both detents, then pulled both shafts out with the forks and selectors in one clump. (Didn't loosen the 1-2 shift fork in other words.)




Only one head scratcher. The tutorial doesn't mention pulling out this shaft with the gear. Luckily there is a photo with it removed so I figured it out. Needed persuasion to move out of the way.





Uh oh. We all know what this means. Looks like the machine shop will be getting some work!




Is this heat bluing I see two places?





Got the diff out. Carrier bearings look the same on both sides.




Thats it for now. Good night everyone!

[Brian911T]

Originally Posted by evan9eleven

That sachs clutch disc looks like the newer verision that came out in 2012 with single springs and 10mm smaller inside diameter. Could help you figure out mileage if you have other receipts. I'm in the process of changing my clutch and here is a pic of the old style and new.




Here is a link discussing it the clutch disc change.

what's with the new sachs clutch discs?

[evan9eleven]

Originally Posted by Brian911T

That sachs clutch disc looks like the newer verision that came out in 2012 with single springs and 10mm smaller inside diameter. Could help you figure out mileage if you have other receipts. I'm in the process of changing my clutch and here is a pic of the old style and new.

Thanks Brian! The PO gave me all his receipts and there was no clutch done after 2012. The PO owned the car then so it remains a mystery and I got the car in 2014. The one thing I'm pretty sure of is that this clutch has plenty of life left so I think I'll just be putting it back in.

[evan9eleven]

Another happy weekend day in the garage!


Lets start with 5th. It shifted just fine so I was hoping to just leave it alone. Upon inspection the syncro doesn't look too healthy. Still, I rarely ever use 5th here in the land of low speed limits...




1st and 2nd syncros, dogs, brake bands and blocks. Obviously the dogs and syncros will get replaced. Brake bands and blocks look ok to me, opinions?









1-2 slider. Well used and will be replaced of course.

[evan9eleven]

Some more bits:

1-2 spider. The wear can't be felt, only seen:



1st gear needle bearing and bushing. I'm going to have to make a decision on replacing these if anyone has wisdom to share:

[Trackrash]

OK, I'll chime in.

That fifth synchro band is toast. However, some mechanics will move a good used one in there with good results. I doubt you need a new 5-R slider, but you might want to check it carefully considering the condition of the synchro.

That 1st gear dog teeth set is showing wear, probably not worth trying to reuse it.

Check the inner bearing race on your 5th gear. Any lines, you will need to replace the gear.

That needle bearing looks great. Unless they show wear or damage, they can be reused.

That spider looks good, as do your brake bands.

That 1 - 2 slider is best replaced with the synchros.

[kevingross]

Originally Posted by evan9eleven

Kevin! Thats a mighty cool homemade backlash tool. Do you have more pictures, especially with it in use? I've ordered a dial gauge and am starting to get my head around the concept and procedure, but exact dial gauge placement and what variation of tool to make are still eluding me.

Hi Evan, busy week, sorry for the delay. Here are a couple of pictures but with a 944-series diff because it was closest to hand.





You can see the lines drawn on the tool. From the center, the line should be 96 mm from the center for a 915 transmission: 80 mm per the workshop manual's instruction for setting the VW 388, plus 16 mm for half the width of the VW 521/4 locking sleeve. I would use an allen bolt and a long allen socket as shown in the second photo for easy of use in attaching the tool: unless you are lucky, you will iterate several times to get the preload and free-play (backlash) just right.

The "U" for the tool should be just wide enough to sit across the differential side sleeve, but not so wide that it hits the case.

I hope this is helpful.

[kevingross]

It's always hard to judge from photos, but the fourth photo showing gear teeth, are the teeth really as scratched up as they appear? Concerning.

[evan9eleven]

Originally Posted by Trackrash

OK, I'll chime in.

That fifth synchro band is toast. However, some mechanics will move a good used one in there with good results. I doubt you need a new 5-R slider, but you might want to check it carefully considering the condition of the synchro.

That 1st gear dog teeth set is showing wear, probably not worth trying to reuse it.

Check the inner bearing race on your 5th gear. Any lines, you will need to replace the gear.

That needle bearing looks great. Unless they show wear or damage, they can be reused.

That spider looks good, as do your brake bands.

That 1 - 2 slider is best replaced with the synchros.

Thanks Gordon! 1st dogs will be replaced. 2nd-4th will be new gears with new dogs from Guard. No chatter lines inside 5th, though the bushing looks iffy (more on that and the slider in a minute.)

[evan9eleven]

Originally Posted by kevingross

Hi Evan, busy week, sorry for the delay. Here are a couple of pictures =snip=

I hope this is helpful.

Thanks Kvein, much appreciated!