Disco 1 Bump and grind :-(

I have a 300Tdi shod in fairly new 205/16 all terrain tyres otherwise pretty standard other than snorkel and steering guard. Having had a great day laning around West Norfolk on my drive home I noticed a single knock every time I applied the foot brake. Now back home, I'm getting a feeling like the brakes are binding when I reverse. The Disco has had quite a bit of use recently but the laning trip was the first time I've applied the diff-lock for a while – it did appear to go in and come out OK, certainly as far as the warning light suggested. Any thoughts please on where I should start my investigations? First thoughts were brakes but I wonder if it could be the transfer box? Thanks in advance.

Jack the back axel up and spin the wheels backwards and it will give you an idea. It should have the same resistance spinning forward and back.

RichardIStone said:

First thoughts were brakes but I wonder if it could be the transfer box?

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If in fact it is the transfer case diff lock stuck on then the vehicle would tend to be binding in both forward and reverse, if you jack one front wheel off the ground and can turn it a turn in either direction that will indicate that your diff lock has disengaged ok.
To check for brake binding just jack one axle, both wheels, off the ground each should rotate reasonably freely, allowing for some transmission/handbrake resistance.
The knocking sound with brakes applied could be one or more of the trailing arm bushing or panhard rod bushing bolts a little loose and allowing the diff housing to move back and forth within the steel bushing that is moulded into the centres of the rubbers, I have experienced this in my D1 after a bit of enthusiastic 4 WDing in wet and muddy conditions, the securing bolts need to be very tight to sandwich the rubber bushing assemblies.

Turns out that the top bolt on the OSF brake caliper is missing, will source a replacement! Thanks for your thoughts.

Hmmm, these caliper bolts have a head that's new to me. I think the name is 12 point? My good old Halfords sockets have twelve points, are these suitable or do I need a special set of sockets for this type of bolt? Part number is FTC3375

Your Halford's 12 pointers should be okay

Thank you.

If you go to Machine Mart they sell a set of sockets which will work on your calliper bolts and torx, spline and hex head bolts, even partly rounded hex bolts, they are quite cheap too only about £12 if I remember correctly for a rail.
Kev

Interesting, thanks Kev - found and ordered