Stripped banjo bolt

I’m in the midst of getting my car ready for a family vacation.

I have always had an issue with and oil leak from my banjo bolt located right up against the firewall on my MK IX. Today I decided to take it all apart and see what was going on. To my absolute horror, when I unscrewed it, it was filled with all of the threads from the soft aluminum head. It is completely stripped.

Short of taking the head off, is there anyway that I can get this car running until the end of summer when I would take the engine out? I am supposed to be taking the car on a holiday on Sunday. The last holiday I took with the car ended up having to be towed home and we canceled the remainder of the holiday. My pride cannot handle another incident like this! (not will my wife’s patients…)

Hoping for someone with a little bit of good news to get me through the holiday,


Get a good machinist to make a longer one from brass , to screw into deeper threads.

I believe many of the vendors actually sell longer banjo bolts (at least thats what I did several years ago on my Mk1. JS

In the UK the longer bolts are supplied by Ken Jenkins; Our car has the same albeit minor leak (most do I believe) but I am leaving it well alone.

Same thing happened on my 120. I made a 1/4" longer bolt. You need to get a tap in there to tap the threads deeper, and be sure to load the tap with grease so you pull out all the chips. You don’t want them getting in the oil passage there. As I recall the tap was either 5/16-18 UNC or 3/8-16 UNC.

Unfortunately, the bolt is already a very long one. It is already 1 inch of thread. It must’ve stripped a few times previously in its life as the stripped aluminum was only on the last 1/4 inch of the thread.

Unless anyone has any other ideas, I think I will cut up a tap to make it short enough to fit behind the engine and see if I can carefully fit a larger bolt in. I like the grease idea to help keep the shavings out. I was thinking I’ll do a quarter turn and remove it so I can suck out shavings. I’ll first spend some time machining a larger banjo bolt.

If anyone has other ideas, I’m all ears.


If you pop off the cover, cam caps and cam, you can flush out the input port to ensure you haven’t missed a shaving which could end up being pushed through with very bad outcome. I haven’t had to resort to using anything longer than the standard bolt. I thought the repair bolts were longer than an inch though. It would be worth a call.

Most importantly, the reason this happens is over torquing to try and staunch a leak. If you use the proper super thin washers with a crush ring you can seal them with very low torque so long as the mating surfaces are flat. Too many people are using thick copper washers, and trying to seal against imperfect surfaces. A little Hylomar on the washer can’t hurt either.

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This is what I’m using…SNG part # C5846/R

Did you have to extend the existing threads to use this or are they already there and not used with the original bolts?

These are the proper washers BTW. Not sure why they’re still selling Stat-os. I think we’ve seen plenty of issues caused by them.!/English/parts/afad3939-d7bd-46ba-8ca7-a8e65559dad8

I’ve had a look at my Stype head today and the depth of the hole is about 40mm on the exhaust side and a little bit more on the inlet side because the head has a bit more metal at the back for the tacho drive.
The thread is 5/16 UNC.


Jeff, thank you so much for your picture of the bolt. Yours was a quarter of an inch longer than mine, and that gave me enough length to get mine to seal again. I thought mine was already at the maximum length, but obviously it was not.

I am just confirming that the oil intake’s from the end of the bolt, because the bolt is within a 16th of an inch from bottoming out right now. I made my own banjo bolt, and tried to make sure that I could get every bit of length on it that I could.

Am I correct that if my banjo bolt is too long, or is clogged, that I would be able to see that there is less oil when I open up the valve cover?

Thank you to everybody for your help. I had already made an oversize bolt, and was trying to figure out all of the ramifications when I got this picture. Luckily, I have not altered anything on the car.


Im 99% sure that I did not have to extended the threads…but it was several years ago. JS

Joel, not sure about the “clogging”…I just bolted mine on and celebrated that I did not have any leaks (also used the really thin/correct washers). JS

It just did 300 miles through the mountains, with no problems. I did notice a slight drop in oil pressure while going up the steepest hills, but will start a new thread to ask the question.

Thanks for everyone’s help!