10 replies to this topic

[croc7]

What’s the best method to remove the water pump bypass tube from the underside of the cylinder head?

[imack]

Personally I'd leave it alone and run with the bypass hose, I've never managed to remove one and you risk damaging the head.

[croc7]

Yes, this thing is pretty stubborn, currently trying penetrating oil. If that doesn’t work, then my only option would be to drill it out and tap for a 5/8 UNF plug.

[DeadSquare]

There isn't a "best method".  If you don't intend to use the bypass, unscrew it before the cylinder head has been used.

 

If you have removed it and wish to clean up the threads........I have been told, but have never verified, that it is the same 5/8" thread as the bolts in either end of the crank.

 

If you have tried to remove it and made a mess of it............

 

The head needs to be securely held under a pillar drill and the tube drilled out with a 19/32" drill.  the hole can then be tapped 3/8" BSP (The thread used for water or gas pipes) and plugged with a brass plug wrapped in PTFE tape..

Edited by DeadSquare, 17 September 2019 - 06:01 AM.

[gazza82]

What’s the best method to remove the water pump bypass tube from the underside of the cylinder head?

Tapping it in from the sides should make it fold in on itself. That's how my busted one came out.

[ACDodd]

They come straight out when you remove the thin section of tube with a cold chisel, then weld in a 10mm bolt. Use the hex to undo the thread with a socket.

Ac

[DeadSquare]

They come straight out when you remove the thin section of tube with a cold chisel, then weld in a 10mm bolt. Use the hex to undo the thread with a socket.

Ac

 

Nice one !

I expect that the heat of the welding has a beneficial effect on the threads.

What do you screw in in its place ?

[Twincam]

http://www.minispare...vos/5-8UNF.aspx

Minispares do a plug

[gazza82]

http://www.minispare...vos/5-8UNF.aspx

Minispares do a plug

 

Not convinced that is the correct thread though .. it may fit cross-threaded and need hylomar to help it seal ..

 

There is/was a proper part ... 88G619 ... but it took me a while to find one and that was the last one on t'internet as far as I could tell!

 

The part I see on sale now with that number do not look like the one I fitted and mine came from a Rover dealer.

Edited by gazza82, 17 September 2019 - 03:20 PM.

[DeadSquare]

The last one that bought and fitted, was from Uniparts 20 years ago.  It was brass, had a head like bolt and used a fiber washer between the bolt head and the cylinder head.

[croc7]

Researched thread size and found it was something not readily available. Took the head to a machine shop to perform surgery on the head. Thanks to all for input.