I towed my boat to Loch Lomond yesterday with the XJ. The boat weighs approx 1 ton and there was a couple of times I had to break quite hard, this is when I got a clunk/knock from the front end that could be felt through the floor too.

The boat trailer is an American Shoreland'r and doesn't have brakes so it was working hard to stop the rig.
Anyone know what might be worn or need replacing?

 

Just to confirm it's only 1 knock, not a series of knocking, and it's under heavy braking not "breaking" and its at the end just before it comes to a standstill.

 

first place i would look would be the caliper bolts/mounts and front brakes.

then check control arm bushings, ball joints and trans mount.

 

It's the pads moving off where they ride and coming back down in there place

 

+1

 

How can the pads move... They are held in quite tightly at both ends with the calliper aren't they?

Took off the wheels and had a look at hubs/brakes..nothing obvious.
Will check control arm bushings next.

Thanks guys

 

Mine does the same thing under hard braking if the spindle is worn where the pads rest on, that's where it jumps when your hard on the brake petal

 

Check the pad-slides for notches. They can get pretty bad...