Roof down, no issues. Roof up, a lot of knocking when turning corners, going over light bumps.
Any ideas? I’m planning on lubing the rubber at the weekend which I hope may help. Thank you.
Funny I was going to post the same. Actually I lubed all the rubber on my PRHT and since then I am getting lots of knocking noise on my hard top when cornering, going on humps and accelerating briskly. It was all fine and knock free before I lubed the rubbers. Any advice?
You’re getting the noises AFTER lubing? Ooops! I was hoping this would fix it.
I’m interested in other experiences with this knocking sound.
Yes, there were no noise before lubing all the rubber. I guess it softened the rubber and roof is now knocking the pillar and windscreen frame.
Apply some grease to the 2 pins that locate the roof to the top of the windscreen. Usually stops the rattle. Paul.
Thanks, but it’s more of a knocking than a rattle and coming from behind me. Initially I thought something was loose in the boot but not the case.
Hmm, two things come to mind as possibles, but they are not the only possibilities.
See this picture below.
The chrome-dome bolts work loose on the deck mechanism, either side. I secured mine with a touch of Medium thread-lock and it cured the problem. Red arrow points to it.
The “roof hook” cable might be wrongly adjusted or loose. Orange arrow points to it.
Roof hook is between the seats and holds the retracted roof in place, but when not in use (ie when the roof is closed) it can rattle a lot with a clonking noise if the cable is slack and nuts loose.
Thank you. I’ll take a look at both of those at the weekend.
Thinking about it, how do I access that mechanism? 
Open the roof but stop, ie take your finger off the button, after the roof has lowered but with the rear deck still as high in the air as you can manage.
Hth and hope you find the source of the rattle sooner.
As MaxBlack says. And different access options depend on lid high or lid low when deck is raised.
Then follow the line of the cable and it SHOULD be clamped in various places, but if it has been out at any time quite likely missing them.
There are Mellens guides on the PRHT etc on WaybackMachine, but they do need donations to exist and keep on helping us.
The guides take some reading and I’ve found a few key bits are missing, but when one has a look at the car most are soon filled in as “obvious” (hmm, really?).
Missing is the actual setting for that cable adjustment. But it might well not be the problem.
The chrome dome bolts are comprehensively covered.
Diagnostic trail for PRHT is here
Lots of drawings and service data buried in here
Thanks. I’ll look through those. However, are you saying the dome bolts are not easy to access?
The Dome bolts are the easiest! The description is comprehensive, ie good coverage.
I would still check the two locating/guide lugs on the front of the roof, sound travels and the rattle/knock that comes from them can sound like it is coming more from behind the driver.
So, one of the dome nuts was slightly loose but not so much that I would have expected the knocking I was hearing. However, I tightened it. The roof hook cable looks ok as far as I can tell, so didn’t adjust anything and the roof hook seems to have no more movement than I would expect. I applied rubber lube all round. Took it out for a good run and 95% better. Still occasional knock when I hit a bump in the road but I feel like it’s coming from this front pins, where it meets the windscreen. I did apply some rubber lube on the pins but is there anything better anybody would recommend?
Thanks guys for all the advice.
The receivers at the front each side are adjustable. I’ve had cause to remove mine for cable routing, DAB aerial/dash cam etc around the rubber trim there. When refitting I put those back in but not fully torqued up and then close the roof catch. It centres the receivers (well I call them that) the cups each side where the pins locate, unlatch the roof again and torque the bolts up. Take a test drive.
For instructions to adjust the closure mechanism see
