I have a 99 Disco that I bought with a blown head gasket. Whilst stripping it down I broke two of the first three rocker arm assembly bolts. I thought it was my undersized wratchet, so I bought a 14mm socket for my half inch drive and still broke three of the remaining five. I was able to remove all of the bolts that broke except the last one which is stuck in the head. Is this a common problem or a predictor of some other evil? Thanks.

 

it is not common, possibly someone used locktite

 

Yeah that's not a good sign. Usually thw rocker arm bolts are easy and the head bolts more difficult. Good luck!

 

It does appear the previous owner used some sort of stop leak in the coolant which was all over the rocker covers.

 

I would run a tap thru all the holes to remove any lock-tite or any other thread locker that is in there. You may have to heat the head around the one you can not get off to liquify the thread locker inside there.