MF135 Cylinder Head Rear Core Plug

[1968 MF135]

Hi,
This weekend the core plug at the back of the cylinder head on my 1968 MF135 decided to spring a large leak (Perkins AD3 152 engine).

Has anyone changed one of these before? Is it possible to replace with the cylinder head attached to the block?

In general I need to know how far to strip down to get good enough access to replace the core plug.

Thanks in advance

 

[1968 MF135]

Apologies - I just had another look, its not in the cylinder head - its at the back of the block at the top.

 

[DJ54]

I assume it's part #6 in this exploded view. https://parts.agcocorp.com/us/en/apbsearch?q=masseyferguson/651199/l&c=74 Part number is 731999M1. M-F dealer price is $5.37, aftermarket a couple bucks. OEM specs show's .891", other show a 7/8" plug. NAPA or any decent parts store should have it.

 

[1968 MF135]

I assume it's part #6 in this exploded view. https://parts.agcocorp.com/us/en/apbsearch?q=masseyferguson/651199/l&c=74 Part number is 731999M1. M-F dealer price is $5.37, aftermarket a couple bucks. OEM specs show's .891", other show a 7/8" plug. NAPA or any decent parts store should have it.

Hi, Thanks for the reply - yes that is the item.

However, My question was how much of a strip would I need to do to replace this? I have fuel tank off now and looking to remove the battery tray structure - then i think I may have just enough room?

If anyone can add anything to this then that would be great thanks.

 

[1968 MF135]

Well I have answered my own question - Stripped out the battery tray and can now get at the core plug.

I would STRONGLY suggest that if you ever split the engine on a 135 then you change this plug as a precaution - as taking out the battery carrier is a hell of a job!

Anyway - I think the plug was ready for replacing looking at the photos below...... Opportunity to clean away the dirt as well.....

 

[1968 MF135]

That's a little better.....

Changed all the other core plugs at the same time as they were all past their best.

While I have it in bits I will fit an alternator conversion and replace the very dodgy looking wiring....

 

[5030]

Not a core plug, It is a FREEZE PLUG and it's there to keep the block from cracking if you don't have any antifreeze in it and it's below freezing. Sure looks better cleaned up too...

 

[1968 MF135]

Not a core plug, It is a FREEZE PLUG and it's there to keep the block from cracking if you don't have any antifreeze in it and it's below freezing. Sure looks better cleaned up too...

Sorry, But in the UK it's a core plug : Wikipedia Link

"The slang term "freeze plug" was coined many decades ago out of ignorance of the true purpose of the core plugs-they were never designed to be displaced by water freezing inside the block due to a lack of an anti-freeze/water mixture; their displacement is merely coincidental if freezing does occur. The sole purpose of a core plug is to literally act as a plug in the holes designed to be in a casting which allows the casting sand to be removed during the manufacturing process."

 

[5030]

Whatever. You never stated where you were at. Still a freeze plug here and a 'Spanner' there... Least you cleaned it up, I'll give you that.

 

[1968 MF135]

Well, in my post above I said that I changed all the other core plugs as a precaution, well, I changed them all apart from the one just behind the injector pump (didn't fancy taking the pump off).

Yes, you guessed it - Fired her up today and that plug decided to start leaking - That will teach me to not do half a job! So my weekend job will be to remove the injector pump and replace that core plug - found a great video for pump timing and removal here:

From what I gather, I can remove the injector pump and put it beck without needing to time the pump as long as the engine is not turned while the pump is off. (please correct me if I'm wrong)