Outbraked by a Ford Focus...
Discussion
MPoxon said:
May I ask which course you booked with CAT. I have always fancied taking the car to Millbrook.
We were on the performance driver day. It was recommended by Jo as a good all round course. Performance Driver Link
When the brakes are sorted and I have finished the course I will do a full write up. The part we did seemed very good.
ChrisPap said:
How's this problem going? Any update?
Thanks for asking. there are quite a few updates 
It isn't fixed though...
I started another thread on Pistonheads after I got an AP Racing adjustable brake bias valve fitted.
So that is the most recent thread.
There are also updates on my TVR blog, which make for very dull reading.
The adjustable valve may be able to fix the problem, but quite possibly only in the region of adjustability where it rattles.
In terms of what I am trying next:
I have been in communication with Ford to find out the specification of the standard brake proportioning valve which is fitted – Ford part 7117274. The initial response from Ford was not helpful but after some further communications it seemed that they would send me the specification. But they sent me some other useless information instead. I have now written a letter. If they can answer my not very hard question this would let me know where in the AP valve’s range of adjustability the standard valve sits.
Changing the front pads for new pads may help. I don’t know the history of the fronts. I have been told they are the correct model and that they have plenty of pad material left, but age is unknown and it is possible that they could be past their best. The knowledge I have of the brake pads is here.
The master cylinder could be faulty. I don’t imagine that would be easy to test so wold probably involve a straightforward swap of old for new at £120 for the cylinder and a fair bit for labour.
Car suspension setup is also an option. It has been looked at by good TVR garages, should be set-up correctly, and handles fine (to me), but maybe there is something that is missing. I am having some checks done by Centre Gravity who have a very good reputation.
I really want to get this sorted and get the car on a track - although that would require a quieter exhaust (currently JP sports exhaust).
More importantly you don't know what pressure is being applied to the front and rear. I personally wouldnt mess about with new valves etc we know the standard set up is pretty good. Everything you do is speculative until you've got some tangibles.
Is everything standard? Are you able to do any of this work your self?
Is everything standard? Are you able to do any of this work your self?
Targarama said:
I still can't believe you haven't changed the front brake pads, they are still an unknown quantity and they could easily have been overheated. Stick some Carbon Lorraine pads in there and you'll not be worrying about the brakes any more.
Sorting this is a slow process - the car works fine for all bar the most extreme braking and I have had other things taking up my time (so I now know that a baby seat fits in the Tamora).I would most likely put in the pads that AP racing / TVR Power supply which are Ferodo DS2500s. These are pads I have used before on other cars and should suit the driving I do. Coefficient of friction I believe is 0.34, lower than the Carbon Lorraine's 0.4 from their RC5+ pad.
m4tti said:
More importantly you don't know what pressure is being applied to the front and rear. I personally wouldnt mess about with new valves etc we know the standard set up is pretty good. Everything you do is speculative until you've got some tangibles.
Is everything standard? Are you able to do any of this work your self?
Getting some tangibles is difficult. What can you suggest would be measured?Is everything standard? Are you able to do any of this work your self?
The idea behind the adjustable valve was that it would do everything the standard valve does plus have some extra adjustability. If I don't need it, I will happily swap to a standard valve and ebay the adjustable one.
The standard setup is indeed supposed to be good. Mine is standard (excluding new valve).
Regarding doing work myself, I would go as far as swapping pads / disks, but I wouldn't remove / refit valves etc.
Edited by Sevenman on Friday 2nd November 13:31
Just come accross this thread ad thought I'd add my tuppence.
I did a Brands GP track day with my T350 a while ago. The brake fade was shockingly bad, and the smoke that came out of the brakes in the pits was quite scary.
After this track day I never really had any more than about 50% brake efficiency.
I was convinced I'd glazed the pads through over heating so swapped them all out for some EBC Redstuff pads (which I've heard mixed reports on to say the least, but they are good value)
At the same time upgraded from GAZ Pro Golds to GAZ Monotubes and had it all corner weighted and checked for camber, caster and toe in(thanks go to Bubble and Kick for that).
Firstly, the GAZ Monos have changed the car more than I can possibly desscribe. Without a doubt the best upgrade I have made to my car. To be honest though, the old shocks had completely the wrong springs on them. Derek from GAZ was rolling his eyes to the sky and muttering about the competency (or lack of) of the particular (Northern) TVR garage who fitted them.
The new shocks have transformed the ride, and its now 100% more comfortable on long journeys, as well as better handling.
Back to the brakes... My old pads (no idea what they were) were indeed knackered. The rears had partially crumbled, and the fronts were glazed. I have seen RedSpike say he doesn't like them, but I can only speak as I find, and must say that the RedStuff pads are a million miles better than the old ones. That's not to say that other more exotic pads won't give you another big leap forward in terms of performance.
A point to bear in mind is the running in on the brakes. My discs were slightly grooved, and I probably should have had them skimmed, but while the pads were running in, they were abysmal in terms of performance, as well as shaking, juddering etc.
For a small outlay a new set of pads is certainly the starting point of any brake related issues you are suffering.
I did a Brands GP track day with my T350 a while ago. The brake fade was shockingly bad, and the smoke that came out of the brakes in the pits was quite scary.
After this track day I never really had any more than about 50% brake efficiency.
I was convinced I'd glazed the pads through over heating so swapped them all out for some EBC Redstuff pads (which I've heard mixed reports on to say the least, but they are good value)
At the same time upgraded from GAZ Pro Golds to GAZ Monotubes and had it all corner weighted and checked for camber, caster and toe in(thanks go to Bubble and Kick for that).
Firstly, the GAZ Monos have changed the car more than I can possibly desscribe. Without a doubt the best upgrade I have made to my car. To be honest though, the old shocks had completely the wrong springs on them. Derek from GAZ was rolling his eyes to the sky and muttering about the competency (or lack of) of the particular (Northern) TVR garage who fitted them.
The new shocks have transformed the ride, and its now 100% more comfortable on long journeys, as well as better handling.
Back to the brakes... My old pads (no idea what they were) were indeed knackered. The rears had partially crumbled, and the fronts were glazed. I have seen RedSpike say he doesn't like them, but I can only speak as I find, and must say that the RedStuff pads are a million miles better than the old ones. That's not to say that other more exotic pads won't give you another big leap forward in terms of performance.
A point to bear in mind is the running in on the brakes. My discs were slightly grooved, and I probably should have had them skimmed, but while the pads were running in, they were abysmal in terms of performance, as well as shaking, juddering etc.
For a small outlay a new set of pads is certainly the starting point of any brake related issues you are suffering.
Sevenman said:
Sorting this is a slow process - the car works fine for all bar the most extreme braking and I have had other things taking up my time (so I now know that a baby seat fits in the Tamora).
I would most likely put in the pads that AP racing / TVR Power supply which are Ferodo DS2500s. These are pads I have used before on other cars and should suit the driving I do. Coefficient of friction I believe is 0.34, lower than the Carbon Lorraine's 0.4 from their RC5+ pad.
I replaced all pads and disks on mine with the ap ferrodo set up including the sagaris upgrade and did a track day with an instructor pushing me. No lock ups and no fade doing 10 laps at a time. I would most likely put in the pads that AP racing / TVR Power supply which are Ferodo DS2500s. These are pads I have used before on other cars and should suit the driving I do. Coefficient of friction I believe is 0.34, lower than the Carbon Lorraine's 0.4 from their RC5+ pad.
m4tti said:
I replaced all pads and disks on mine with the ap ferrodo set up including the sagaris upgrade and did a track day with an instructor pushing me. No lock ups and no fade doing 10 laps at a time.
Is the Sagaris update bigger disks? Given the weight of the car, DS2500s should be up to trackdays given how well they used to work on my heavy Saab Turbo that had smaller disks.
Sevenman said:
Is the Sagaris update bigger disks?
Given the weight of the car, DS2500s should be up to trackdays given how well they used to work on my heavy Saab Turbo that had smaller disks.
I'm running DS2500s at the moment, they are more than capable for track days. The Carbon Lorraine pads are pretty damn awesome in terms of stopping power though - I just couldn't stand the squealing (doesn't affect all cars - yes my pads were installed and greased etc. by Str8Six).Given the weight of the car, DS2500s should be up to trackdays given how well they used to work on my heavy Saab Turbo that had smaller disks.
Sevenman said:
Getting some tangibles is difficult. What can you suggest would be measured?
The idea behind the adjustable valve was that it would do everything the standard valve does plus have some extra adjustability. If I don't need it, I will happily swap to a standard valve and ebay the adjustable one.
The standard setup is indeed supposed to be good. Mine is standard (excluding new valve).
Regarding doing work myself, I would go as far as swapping pads / disks, but I wouldn't remove / refit valves etc.
I think on your other thread I linked to a brake pressure test kit so you could determine what pressure is reaching the front and rear calipers. I think till someone determines this you won't be able to clearly ascertain where the fault lies. The idea behind the adjustable valve was that it would do everything the standard valve does plus have some extra adjustability. If I don't need it, I will happily swap to a standard valve and ebay the adjustable one.
The standard setup is indeed supposed to be good. Mine is standard (excluding new valve).
Regarding doing work myself, I would go as far as swapping pads / disks, but I wouldn't remove / refit valves etc.
Edited by Sevenman on Friday 2nd November 13:31
I'm quite suprised that you haven't been able to get this sorted yet. It should have been relatively easy to troubleshoot.
My only suspicion is with your braking system. Tyres would have to be terribly out of whack, and likewise suspension would have to be rediculous before you start locking rears consistently. To the point where I'm sure you'd notice other problems.
My first suspicion would be Brake calipers themselves or pads. I'd check that all pistons were working without any siezed ones. This can be done just by taking the wheels off and having two people available. Then check pads to make sure that they're at least servicable. If all checks out I'd be looking at the brake maser cylinder. I'm not sure what system the TVR has, diagonal split, 2 front and one rear, or front and rear lines only. Whatever way, if the cylinder bore is scored it could easily affect brake performance. Proportioning valve would have been the last place I'd look because they almost never go wrong.
I'd also be looking mostly at the front end because it's far more likely that the front brakes are underperforming than the rear brakes are overperforming.
I'll happy have a look over it with you if the weather is not too moody next weekend and if you can get the car over to Buckingham MK18.
My only suspicion is with your braking system. Tyres would have to be terribly out of whack, and likewise suspension would have to be rediculous before you start locking rears consistently. To the point where I'm sure you'd notice other problems.
My first suspicion would be Brake calipers themselves or pads. I'd check that all pistons were working without any siezed ones. This can be done just by taking the wheels off and having two people available. Then check pads to make sure that they're at least servicable. If all checks out I'd be looking at the brake maser cylinder. I'm not sure what system the TVR has, diagonal split, 2 front and one rear, or front and rear lines only. Whatever way, if the cylinder bore is scored it could easily affect brake performance. Proportioning valve would have been the last place I'd look because they almost never go wrong.
I'd also be looking mostly at the front end because it's far more likely that the front brakes are underperforming than the rear brakes are overperforming.
I'll happy have a look over it with you if the weather is not too moody next weekend and if you can get the car over to Buckingham MK18.
Edited by ChrisPap on Friday 2nd November 21:46
m4tti said:
I think on your other thread I linked to a brake pressure test kit so you could determine what pressure is reaching the front and rear calipers. I think till someone determines this you won't be able to clearly ascertain where the fault lies.
You did, and you had answered my question on the Sagaris upgrade.I am certainly considering the pressure testing, but I am hoping some of the other checks / research I am doing, the visit to a suspension specialist, and a change of the front pads will sort it. If not, it could be an option.
ChrisPap said:
I'm quite suprised that you haven't been able to get this sorted yet. It should have been relatively easy to troubleshoot.
My only suspicion is with your braking system. Tyres would have to be terribly out of whack, and likewise suspension would have to be rediculous before you start locking rears consistently. To the point where I'm sure you'd notice other problems.
I am surprised it hasn't been sorted as well. Tyres are all good (fitted in April) and I believe suspension is fine (fitted July 2011) but the tests later this month should confirm it.My only suspicion is with your braking system. Tyres would have to be terribly out of whack, and likewise suspension would have to be rediculous before you start locking rears consistently. To the point where I'm sure you'd notice other problems.
ChrisPap said:
My first suspicion would be Brake calipers themselves or pads. I'd check that all pistons were working without any siezed ones. This can be done just by taking the wheels off and having two people available. Then check pads to make sure that they're at least servicable. If all checks out I'd be looking at the brake maser cylinder. I'm not sure what system the TVR has, diagonal split, 2 front and one rear, or front and rear lines only. Whatever way, if the cylinder bore is scored it could easily affect brake performance. Proportioning valve would have been the last place I'd look because they almost never go wrong.
I'd also be looking mostly at the front end because it's far more likely that the front brakes are underperforming than the rear brakes are overperforming.
I'll happy have a look over it with you if the weather is not too moody next weekend and if you can get the car over to Buckingham MK18.
I suspect underperforming due to pads / bias valve, although the master cylinder is an option (£120 + fitting). I did have the adjustable bias valve in a position where the fronts locked first (but then struggled to repeat it), and it has been braking evenly, not pulling to either side.I'd also be looking mostly at the front end because it's far more likely that the front brakes are underperforming than the rear brakes are overperforming.
I'll happy have a look over it with you if the weather is not too moody next weekend and if you can get the car over to Buckingham MK18.
I believe the TVR has separate front / rear circuits rather than diagonals. I hope I / the TVR garage are not wrong, as if it is diagonal 2 bias valves are needed... I am pretty sure it is separate front / back
Should be easier to find out when it is up on a lift for suspension work.
Thanks for the offer of helping with a look-over of the car. I will see what happens after the suspension checks and front pad swap later this month and how much progress has been made.
Hopefully it will be 3rd time lucky and Ford will answer my question on the bias valve.
HarryW said:
Would a MOT type brake force testing rig be able to tell you something that may help here........
Not sure - never seen one in action.The brakes have passed an MOT in their current configuration. I thought they tended to measure across an axle to make sure they were balanced, rather than the front-back balance that would require 2 sets of rollers.
Targarama said:
I still can't believe you haven't changed the front brake pads, they are still an unknown quantity and they could easily have been overheated. Stick some Carbon Lorraine pads in there and you'll not be worrying about the brakes any more.
you mean those pads that tend to break easily? (and no that isn't a typing mistake)PascalBuyens said:
Targarama said:
I still can't believe you haven't changed the front brake pads, they are still an unknown quantity and they could easily have been overheated. Stick some Carbon Lorraine pads in there and you'll not be worrying about the brakes any more.
you mean those pads that tend to break easily? (and no that isn't a typing mistake)Another option are Pagid RS14, love them but if these were on the back and standard pads on the front then I would be locking the rears constantly, can not believe that OP has not changed the pads to same all round and not cheap EBC either, had far to many instances of brakes fading to nothing with those pads to ever return.
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