How to identify pump sprocket bolts

[markward]

Hello, I don't normally work on TDI's and when I did my timing belt on my ALH I replaced the pump bolts that can be reused.

We have an ALH 1.9 that is new to us getting the head replaced. The owner has no idea if the pump bolts have been updated. Unfortunately, it's been so long I can't visually identify them.

I tried searching, but came back with too many hits. Anyone able to point me to a thread that shows the difference? I was hoping to get the belt back on today, but may just order new bolts, but that does delay the job.

thank you. Mark

 

[mr.loops]

If the bolts are tapered at the head end then they are TTT and need to be replaced.

Non-tapered bolts can be reused

Like this:
https://images.app.goo.gl/Qj7cnd4fVQVkvFv17


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[markward]

Thanks, Tapered at the head? Not sure what that means. The pump sprocket slots are pretty beat, so I'm going to replace the sprocket and the bolts as a set. Thank you though. Mark

 

[Powder Hound]

The original TTY bolts have only a short shaft for the elongation to happen, so it is a smaller diameter than current reusable bolts. In addition, this short part has no threads. The bolt that has threads completely up the shaft to the head is the reusable one. Hopefully this description is adequate; I have no photos to use for comparison.

Cheers,

PH

 

[JB05]

IIRC, my Bentley Service Manual has a pic of the TTY vs. non TTY bolts. It would take me a while to find it.

 

[markward]

This engine was adapted to a strictly mechanical pump recently. The slots in the sprocket where you would adjust the timing are so hammered that I decided to not reuse the sprocket. Ordering new sprocket and bolts today.


Either someone was making multiple attempts to set the pump timing or at some point the sprocket was loose. Either way, I don't want the next shop that looks at it to think I left something loose.

I looked in my Bentley manual, but it's on CD and is a very early version and I did not find the bolt image you reference, but do remember seeing the image at one point long ago somewhere. Thanks to those that posted.

 

[mr.loops]

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[markward]

Ha, the bolts I removed look nothing like either image. Thank you. Mark

 

[BobnOH]

Originals are silver, replacement non-TTY are gold colored.

 

[wonneber]

Thanks, Tapered at the head? Not sure what that means. The pump sprocket slots are pretty beat, so I'm going to replace the sprocket and the bolts as a set. Thank you though. Mark

Do not loosen the center nut on the pump.
If you do the 'plate' will have to be re-timed for the car to run right.

 

[JB05]

Page 23-19 show the above photo as a diagram with the same info: Version A is the TTY bolt with a chamfer on the shaft and a pointed end; Version B has no chamfer and a flat end which is the reusable bolt.

 

[jimbote]

necked down* under the bolt head