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Post by bigbaldiebloke on Jul 22, 2015 14:50:03 GMT
I've restored my v8 coupe. On the road when I brake moderate to hard something lurches forward.It makes an almighty clunk and the car shifts like a bag of concrete has come from back to front. It's clearly gravity related because this week during the MoT on the rolling road the refurbed brakes surprised the tester who wasn't expecting them to be that good (excluding handbrake). No noise, equal breaking all round no clunking, shifting. Any ideas of the list of things I should check?
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Post by johnwp5bcoupe on Jul 22, 2015 15:40:17 GMT
I've restored my v8 coupe. On the road when I brake moderate to hard something lurches forward.It makes an almighty clunk and the car shifts like a bag of concrete has come from back to front. It's clearly gravity related because this week during the MoT on the rolling road the refurbed brakes surprised the tester who wasn't expecting them to be that good (excluding handbrake). No noise, equal breaking all round no clunking, shifting. Any ideas of the list of things I should check? If your sure its not brake related? check gearbox mount, subframe mounts and engine mounts for a start!! The Handbrake if everything is as it should be and set up correctly will be near enough as good as the Hydraulic brake  |
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Post by bigbaldiebloke on Jul 22, 2015 21:27:37 GMT
Thank you. Transmission/gear box mounts next on the list. G
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Post by enigmas on Jul 22, 2015 22:42:48 GMT
All the above, but probably inertia related. Consider that the subframe, engine, transmission, steering and suspension as a unit, can all move about on their own independent of the main body structure causing a range of disconcerting handling issues to varying degrees. This is especially noticeable if the subframe is not appropriately constrained by the rubber cushioned subframe mounts.
These are now 50 plus years old if original. If their 'working' environment has been subjected to extremes of weather (heat, salt, corrosion and oil) the mount will be compromised.
There are a range of fixes to remedy this, some more amenable than others, dependent upon individual, corrective viewpoints.
A heavy clunk on braking is usually due to rotted suspension rubbers on the DS torque arm at rear. This allows the arm to move back and forth under braking, causing all sorts of issues with both braking and steering quality.
The problem generally originates with the leaking power steering box, an issue never satisfactorily corrected by the factory. Effective non factory fixes have been carried out by many individuals on this forum.
You should find a broad church of views to your concerns here.
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Post by bigbaldiebloke on Jul 23, 2015 13:08:32 GMT
Thank you. That makes complete sense. I'm gradually getting through replacing the rubbers but I've not done those. More Wadham rubber orders.
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Post by johnwp5bcoupe on Jul 23, 2015 14:13:47 GMT
A heavy clunk on braking is usually due to rotted suspension rubbers on the DS torque arm at rear. This allows the arm to move back and forth under braking, causing all sorts of issues with both braking and steering quality. I have lost something in the translation Vince |
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Post by Deleted on Jul 23, 2015 15:11:23 GMT
Hope this isn't going to sound silly but it's not something unrestrained in the boot is it? Is the battery firmly secured?
You haven't been returning to Blighty via Calais recently have you?!
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Post by enigmas on Jul 23, 2015 21:54:27 GMT
No, I don't believe so John. If the rubber bushes have been continually oil soaked,they rot and break up. This allows the lower suspension assembly to move back and forth at the rear in the housing where the rod is secured and designed to pivot (cushioned by the bushes)
Before the PS box on my car was re-engineered to make it oil tight and when it was used daily the same situation occurred.
The rotted bushes also affect the minimal caster the car has under braking on that particular side, causing it to veer.
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Post by johnwp5bcoupe on Jul 24, 2015 6:12:37 GMT
Hi Vince I am not saying I disagree with you it was the names/description :- "on the DS torque arm at rear" which lost me  |
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Post by enigmas on Jul 24, 2015 8:15:23 GMT
That's fine John, I didn't think you were disagreeing with what I said...I was just trying to clarifying what can occur if the bushes have rotted.
It's very easy when 'rebuilding' the (front) brakes to forget to check the compound effects of interconnected suspension components such as: loose wheel bearings, worn/rotted suspension bushes, slack top/bottom balljoints and suspect tie rod ends.
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Post by bigbaldiebloke on Jul 24, 2015 13:19:40 GMT
I've certainly neglected those in my eagerness to have it out in the summer. It's definitely not any immigrants in the boot. They would be suffering from the exhaust gas. The sound and inertia impact is definitely under the engine, bulk head / seats. I'll go with Vince. Gareth
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Post by johnwp5bcoupe on Jul 24, 2015 13:25:09 GMT
I would check the simple ones first like the GB Mount, Engine mounts and all the Subframe Mounts including the 2 rears then as vince says check every B thing associated with rubber!!
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