Ka Brake servo and m/c.......which one?
Discussion
just found out - a coupe of hours ago - that the servo and master cylinder are fubard.
Its a G reg S (1.5?) and looks like Ford.
As I've fitted 287mm discs and AP 4 pots front and converted the rears to discs too, then I think I could use a servo/master cyl from a more modern TVR (Ford Ka?)
Any one know which year/model used a one with 22.2mm dia cylinder?
Its a G reg S (1.5?) and looks like Ford.
As I've fitted 287mm discs and AP 4 pots front and converted the rears to discs too, then I think I could use a servo/master cyl from a more modern TVR (Ford Ka?)
Any one know which year/model used a one with 22.2mm dia cylinder?
Lots has indeed been written about the servos that can be fitted on the S type, BUT, what has been specified is for a standard system. Yours is not standard either at the front or rear and will need a different displaced volume than standard. It is extremely unlikely that the 'standard' servo and master cylinder recommended will be right for you. I suspect you may also need a different front/back bias valve or limiter as well or rear brake lock ups are very likely.
If you can identify another (presumably Ford) vehicle with exactly the same brake specification as yours then if you let me have that information I can look up the Lucas/TRW specification sheets to see what master cylinder and servo spec would be appropriate.
If you can identify another (presumably Ford) vehicle with exactly the same brake specification as yours then if you let me have that information I can look up the Lucas/TRW specification sheets to see what master cylinder and servo spec would be appropriate.
greymrj said:
Lots has indeed been written about the servos that can be fitted on the S type, BUT, what has been specified is for a standard system. Yours is not standard either at the front or rear and will need a different displaced volume than standard. It is extremely unlikely that the 'standard' servo and master cylinder recommended will be right for you. I suspect you may also need a different front/back bias valve or limiter as well or rear brake lock ups are very likely.
If you can identify another (presumably Ford) vehicle with exactly the same brake specification as yours then if you let me have that information I can look up the Lucas/TRW specification sheets to see what master cylinder and servo spec would be appropriate.
Hi greymrjIf you can identify another (presumably Ford) vehicle with exactly the same brake specification as yours then if you let me have that information I can look up the Lucas/TRW specification sheets to see what master cylinder and servo spec would be appropriate.
my setup is very similar to the Griff except for slightly larger front discs (297 instead of 260) which a lot of Griff owners have fitted.
Also yes I have fitted an adjustable limiter to the rears
The T-cars use the Ka 96-08 servo, like this http://www.ebay.co.uk/itm/FORD-KA-1-3-1-6-BRAKE-SE...
If you get an ABS master cylinder, it's available in 22.2mm bore. The non-abs is only 20.6mm
If this is good enough for the TVR Tuscan, T350 etc with 4 pot fronts and rear discs, I'm sure it will work for the S.
The Fiesta cylinder is readily available still, but will not fit the Ka servo.
The operating fork on the servo is about 15mm shorter than the old Fiesta one, so either you can extend it or modify the pedal.
If you get an ABS master cylinder, it's available in 22.2mm bore. The non-abs is only 20.6mm
If this is good enough for the TVR Tuscan, T350 etc with 4 pot fronts and rear discs, I'm sure it will work for the S.
The Fiesta cylinder is readily available still, but will not fit the Ka servo.
The operating fork on the servo is about 15mm shorter than the old Fiesta one, so either you can extend it or modify the pedal.
My apologies if I am 'teaching grandma to suck eggs'!
If you are sure your system is the same as a Griff in terms of the swept/displaced volume needed at the master cylinder to operate the slave cylinders correctly, then you need to know the dimensions of the Griff slave (diameter AND required piston travel) and to match it with both master cylinder and servo.
Over servoing could be just as dangerous as under-capacity.
If you are sure your system is the same as a Griff in terms of the swept/displaced volume needed at the master cylinder to operate the slave cylinders correctly, then you need to know the dimensions of the Griff slave (diameter AND required piston travel) and to match it with both master cylinder and servo.
Over servoing could be just as dangerous as under-capacity.
greymrj said:
My apologies if I am 'teaching grandma to suck eggs'!
If you are sure your system is the same as a Griff in terms of the swept/displaced volume needed at the master cylinder to operate the slave cylinders correctly, then you need to know the dimensions of the Griff slave (diameter AND required piston travel) and to match it with both master cylinder and servo.
Over servoing could be just as dangerous as under-capacity.
Cheers for the heads up. Yes I'm sure I have the same discs and calipers.If you are sure your system is the same as a Griff in terms of the swept/displaced volume needed at the master cylinder to operate the slave cylinders correctly, then you need to know the dimensions of the Griff slave (diameter AND required piston travel) and to match it with both master cylinder and servo.
Over servoing could be just as dangerous as under-capacity.
Got to say I'm with Mr offshore on this one, there must be dozens if not hundreds of S's, Chimaeras, Griffiths etc. running around with all manner of "up-graded" front brakes, bigger calipers, four pots and so on, and I bet less than a handful with any changes to servo or mastercylinder?
mikel003003 said:
Philpot, are you still running on those dinner plate disks ? Are you useing the original spec servo and balance valve ?
Was getting some "brake judder" with the 278mm discs so currently I'm running on some hand me down Chimaera 260mm side plates 
Recently treated myself to a dial gauge and magnetic base so when I'm in the mood can try taking some measurements and see if anything shows up.
Fiesta servo and master cylinder, was nothing wrong with the Saab servo (gave it away before I realised how rare they are), but didn't like the remote reservoir.
Standard balance valve, do wonder if I should have the V8s one as I have converted to rear discs, or do they all do the same? Guess TVR must have changed it for a reason?
If it wasn't such a flaff to do it I'd like to try it without one but would also have to co-incide it with needing new tyres or risk "flat spotting" good tyres with some serious testing!
Sorry folks, jump on me if you like, but there are good engineering reasons why there are hundreds of different master cylinders and servos out there.
I have the Lockheed/Delphi catalogue >2006 in front of me.
Even the Ka, which only had the 1.3i engine had TWO different master cylinders, the 20.6mm bore fitted to the non ABS an the 22.2mm fitted to the ABS cars, as they require different performance characteristics.
If you were to look back on the detailed notes re the alternatives to the SAAB set up you will find small differences in servo rod lengths which effect the point at which the master cylinder starts to operate which can create a tiny delay in pressure to the wheel cylinders.
Granada Mk2, 3 different cylinders, 3 different bores.
Fiesta, one single typical model and engine configuration; 2 different cylinders of the SAME bore producing subtly different performance characteristics when fitted to the same servo.
When we looked at the alternatives to the set up on the S we actually spoke to TRW (who took over the Lucas brake production) and were warned about the range of problems and dangers that could arise if the 'master' side of a brake system wasn't correctly matched to the 'slave' side, both in terms of performance and insurance issues.
Shame Norman isn't involved anymore!
OK, OK, I know you don't want to hear so I think I had better shut up and keep my head down while the bullets fly!!
I have the Lockheed/Delphi catalogue >2006 in front of me.
Even the Ka, which only had the 1.3i engine had TWO different master cylinders, the 20.6mm bore fitted to the non ABS an the 22.2mm fitted to the ABS cars, as they require different performance characteristics.
If you were to look back on the detailed notes re the alternatives to the SAAB set up you will find small differences in servo rod lengths which effect the point at which the master cylinder starts to operate which can create a tiny delay in pressure to the wheel cylinders.
Granada Mk2, 3 different cylinders, 3 different bores.
Fiesta, one single typical model and engine configuration; 2 different cylinders of the SAME bore producing subtly different performance characteristics when fitted to the same servo.
When we looked at the alternatives to the set up on the S we actually spoke to TRW (who took over the Lucas brake production) and were warned about the range of problems and dangers that could arise if the 'master' side of a brake system wasn't correctly matched to the 'slave' side, both in terms of performance and insurance issues.
Shame Norman isn't involved anymore!
OK, OK, I know you don't want to hear so I think I had better shut up and keep my head down while the bullets fly!!
I agree with jw
I purchased NEW Ka master cylinder (correct 22.2 bore) for £80 and a good pre-owned! 2002 servo for £20 (guaranteed and tested)
I feel confident as the rest of the brakes are as usual upgrades for Griffith etc. AP racing 4 pots (ex Griff) and rear disc conversion (again using ex Griff calipers) so using the same master cylinder and servo should work too. (I have an adjustable limiting valve for the rear brakes) and will be fitting a hydraulic handbrake too.
I purchased NEW Ka master cylinder (correct 22.2 bore) for £80 and a good pre-owned! 2002 servo for £20 (guaranteed and tested)
I feel confident as the rest of the brakes are as usual upgrades for Griffith etc. AP racing 4 pots (ex Griff) and rear disc conversion (again using ex Griff calipers) so using the same master cylinder and servo should work too. (I have an adjustable limiting valve for the rear brakes) and will be fitting a hydraulic handbrake too.
Edited by magpies on Wednesday 16th October 13:21
Edited by magpies on Wednesday 16th October 13:26
I think I am slightly disappointed it took 2 hours for the first bullet, and then it was a fairly gentle one!
Jonathan does make a perfectly valid point, but we have TWO separate issues here:
1. the original post was about matching a master cylinder arrangement to a NON STANDARD slave arrangement.
2. the second point, well made by Jonathan, is that we cannot rely on the specified alternative master cylinder/servo (i.e. the specified Fiesta one) for ever as a replacement in the STANDARD car.
1. My main point was that you do have to be very careful to match the 'master' to the demands of the 'slave' cylinders. We know the correct Fiesta master/servo EXACTLY matches the specified performance of the old SAAB units. But, almost by definition, it will almost certainly not be right if you change slave cylinders. It MAY be close enough, I simply do not know. What I do not want is an S being written off, and or someone being killed or injured because it wasn't quite close enough!
The 22.2mm option from the Ka my be closely matched to the slave cylinders in the T's, TVR will have been required to prove that as part of the type approval. But the brake 'slaves' on the T are not the same as those on an S. To exaggerate; I cannot take the master cylinder off a Focus ST3 and ASSUME it will work OK on a Focus Studio, or vice versa.
If Mick (the original poster) has changed his brakes 'all' he needs to do is to find out from the supplier (or, very preferably, from the manufacturer) whether any change in swept volume is involved and therefore any change in master cylinder.
2. What do we do when the supply of the correct Fiesta unit dries up? It took days to research the correct parts that would exactly replace the SAAB unit in terms of performance specification, AND could be made to fit on the S without substantial modification. We acquired samples (via the Car Component Company in Blackburn)and studied them, and we had catalogues and computer data lent by manufacturers, we also talked to TRW as the successor to Lucas who had made both the SAAB and the Fiesta master cylinders and servos. There was more to it than we had thought!
I would be prepared in principle to do that exercise again and to try to come up with part numbers which will provide a performance that exactly matches the original AND is in current production.
BUT I cannot do it in a week or two, and I would need to know that there is a demand.
Incidentally, I have been in contact with Norman, and taken account of his views. We both feel that messing around with master/slave combinations without sufficient research is a recipe for disaster.
And we are both frustrated that we seem to go over the same ground far too often, anything carefully researched is soon overlooked.
Jonathan does make a perfectly valid point, but we have TWO separate issues here:
1. the original post was about matching a master cylinder arrangement to a NON STANDARD slave arrangement.
2. the second point, well made by Jonathan, is that we cannot rely on the specified alternative master cylinder/servo (i.e. the specified Fiesta one) for ever as a replacement in the STANDARD car.
1. My main point was that you do have to be very careful to match the 'master' to the demands of the 'slave' cylinders. We know the correct Fiesta master/servo EXACTLY matches the specified performance of the old SAAB units. But, almost by definition, it will almost certainly not be right if you change slave cylinders. It MAY be close enough, I simply do not know. What I do not want is an S being written off, and or someone being killed or injured because it wasn't quite close enough!
The 22.2mm option from the Ka my be closely matched to the slave cylinders in the T's, TVR will have been required to prove that as part of the type approval. But the brake 'slaves' on the T are not the same as those on an S. To exaggerate; I cannot take the master cylinder off a Focus ST3 and ASSUME it will work OK on a Focus Studio, or vice versa.
If Mick (the original poster) has changed his brakes 'all' he needs to do is to find out from the supplier (or, very preferably, from the manufacturer) whether any change in swept volume is involved and therefore any change in master cylinder.
2. What do we do when the supply of the correct Fiesta unit dries up? It took days to research the correct parts that would exactly replace the SAAB unit in terms of performance specification, AND could be made to fit on the S without substantial modification. We acquired samples (via the Car Component Company in Blackburn)and studied them, and we had catalogues and computer data lent by manufacturers, we also talked to TRW as the successor to Lucas who had made both the SAAB and the Fiesta master cylinders and servos. There was more to it than we had thought!
I would be prepared in principle to do that exercise again and to try to come up with part numbers which will provide a performance that exactly matches the original AND is in current production.
BUT I cannot do it in a week or two, and I would need to know that there is a demand.
Incidentally, I have been in contact with Norman, and taken account of his views. We both feel that messing around with master/slave combinations without sufficient research is a recipe for disaster.
And we are both frustrated that we seem to go over the same ground far too often, anything carefully researched is soon overlooked.
greymrj said:
I think I am slightly disappointed it took 2 hours for the first bullet, and then it was a fairly gentle one!
Jonathan does make a perfectly valid point, but we have TWO separate issues here:
1. the original post was about matching a master cylinder arrangement to a NON STANDARD slave arrangement.
2. the second point, well made by Jonathan, is that we cannot rely on the specified alternative master cylinder/servo (i.e. the specified Fiesta one) for ever as a replacement in the STANDARD car.
1. My main point was that you do have to be very careful to match the 'master' to the demands of the 'slave' cylinders. We know the correct Fiesta master/servo EXACTLY matches the specified performance of the old SAAB units. But, almost by definition, it will almost certainly not be right if you change slave cylinders. It MAY be close enough, I simply do not know. What I do not want is an S being written off, and or someone being killed or injured because it wasn't quite close enough!
The 22.2mm option from the Ka my be closely matched to the slave cylinders in the T's, TVR will have been required to prove that as part of the type approval. But the brake 'slaves' on the T are not the same as those on an S. To exaggerate; I cannot take the master cylinder off a Focus ST3 and ASSUME it will work OK on a Focus Studio, or vice versa.
If Mick (the original poster) has changed his brakes 'all' he needs to do is to find out from the supplier (or, very preferably, from the manufacturer) whether any change in swept volume is involved and therefore any change in master cylinder.
2. What do we do when the supply of the correct Fiesta unit dries up? It took days to research the correct parts that would exactly replace the SAAB unit in terms of performance specification, AND could be made to fit on the S without substantial modification. We acquired samples (via the Car Component Company in Blackburn)and studied them, and we had catalogues and computer data lent by manufacturers, we also talked to TRW as the successor to Lucas who had made both the SAAB and the Fiesta master cylinders and servos. There was more to it than we had thought!
I would be prepared in principle to do that exercise again and to try to come up with part numbers which will provide a performance that exactly matches the original AND is in current production.
BUT I cannot do it in a week or two, and I would need to know that there is a demand.
Incidentally, I have been in contact with Norman, and taken account of his views. We both feel that messing around with master/slave combinations without sufficient research is a recipe for disaster.
And we are both frustrated that we seem to go over the same ground far too often, anything carefully researched is soon overlooked.
Thank you mr grey for this very valuable info....interesting reading and very true.....I do believe we are at the point where the exercise is due. Although I have purchased Ka items, the car will probably not be put on the road until March (ish) next year and if shown to be inappropriate I will remove and fit other recommended items. I will also test drive my car on a private (can be hired) nearby cart racing circuit in Teesside, prior to any public road driving.Jonathan does make a perfectly valid point, but we have TWO separate issues here:
1. the original post was about matching a master cylinder arrangement to a NON STANDARD slave arrangement.
2. the second point, well made by Jonathan, is that we cannot rely on the specified alternative master cylinder/servo (i.e. the specified Fiesta one) for ever as a replacement in the STANDARD car.
1. My main point was that you do have to be very careful to match the 'master' to the demands of the 'slave' cylinders. We know the correct Fiesta master/servo EXACTLY matches the specified performance of the old SAAB units. But, almost by definition, it will almost certainly not be right if you change slave cylinders. It MAY be close enough, I simply do not know. What I do not want is an S being written off, and or someone being killed or injured because it wasn't quite close enough!
The 22.2mm option from the Ka my be closely matched to the slave cylinders in the T's, TVR will have been required to prove that as part of the type approval. But the brake 'slaves' on the T are not the same as those on an S. To exaggerate; I cannot take the master cylinder off a Focus ST3 and ASSUME it will work OK on a Focus Studio, or vice versa.
If Mick (the original poster) has changed his brakes 'all' he needs to do is to find out from the supplier (or, very preferably, from the manufacturer) whether any change in swept volume is involved and therefore any change in master cylinder.
2. What do we do when the supply of the correct Fiesta unit dries up? It took days to research the correct parts that would exactly replace the SAAB unit in terms of performance specification, AND could be made to fit on the S without substantial modification. We acquired samples (via the Car Component Company in Blackburn)and studied them, and we had catalogues and computer data lent by manufacturers, we also talked to TRW as the successor to Lucas who had made both the SAAB and the Fiesta master cylinders and servos. There was more to it than we had thought!
I would be prepared in principle to do that exercise again and to try to come up with part numbers which will provide a performance that exactly matches the original AND is in current production.
BUT I cannot do it in a week or two, and I would need to know that there is a demand.
Incidentally, I have been in contact with Norman, and taken account of his views. We both feel that messing around with master/slave combinations without sufficient research is a recipe for disaster.
And we are both frustrated that we seem to go over the same ground far too often, anything carefully researched is soon overlooked.
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