Hi all,
I have just purchased a very nice Tiger Supercat that has recently passed its IVA. I am concerned at the distinct lack of braking power however, and
would just like some feedback and peoples thoughts.
It has decent Hispec front calipers with greenstuff pads on the front, and standard sierra drums on the rear.
Considering the weight of the car and the decent front calipers I was expecting it to work pretty well, however I have to really stamp on the brakes
in order to get the slowing down process to start!
This is my first kit car so I dont know whether this is the expected performance level of this setup and that my perceived problem is not really a
problem - they are just poor compared to modern cars and what I am used to. Or, there is something wrong - brakes not bled properly or something else.
I wouldnt be suprised if the rear drums were doing all the braking, thats how bad I think the braking is!
Apparently it passed the IVA and the braking felt the same then as it is now, so is this just me and are my expectations too high?
Thanks
Ask local mot centre to check on their machine cost £10 or bleed the system and see as sound like air in the system.
Well it won't have a servo so will feel considerably different to a modern tin-top. Can you lock the wheels on an emergency with a good
shove?
Performance pads (depending on compound) can need a fair bit of warming up before they really start to perform, especially hard if you have vented
discs. Once hot though they should be able to throw you against the belts if you stamp on them.
Could be many thing, though passing IVA is a good sign that they are at least safe.
Brakes not bled would feel spongy - if you have a firm pedal it's probably not that. Next stop would be the pedal box, with pivot points and
actuator rod lengths to be considered along with cylinder sizes.
Don't worry too much about drums on the back as they'll be doing very little compared with the fronts.
I'm sure someone with a similar set up will be along soon to compare notes.
IMO the Master cyl is incorrectly sized to the Bespoke Calipers. Result is poor to No braking.
Unless a Gorilla is available to stomp the brake pedal.
Common beginner mistake (all Too common) Once you've figured out the correct bore size master, appropriate to the fitted calipers Then you needs
find/buy and retrofit the rascal. Easier said than done unfortunately.
Lesson (if there IS one) is to TEST DRIVE any care ...before ...handing over yer $$
The hispecs are absolute crap. They do stop the car if you really push hard but have no feel and are extremely wooden. Bin them and get some wilwoods.
Pedal effort to stop a given car really depends on two factors hydraulic pressure and pad friction material.
I assume your car has a Sierra master cylinder mounted with out a servo. The hydraulic pressure is low for a given amount of pedal force because
the Sierra master cylinder is designed to work with servo. Master cylinders fitted to servo systems have a larger bore than those fitted non-servoed
systems. Also in a Seven style car because of restricted space in the foot well the pedal leverage ratio is about half that of a Sierra. A lot
of people on the forum have converted to Fiat or early Fiesta or early VW Polo master cylinders to reduce the required pedal force to stop the car.
If you do a forum search on "Fiat master cylinder" it should turn up details on swapping master cylinders.
Provided the callipers are sized correctly the make of calliper has absolutely no effect on the pedal force required to stop the car, however
multi-pot alloy callipers can cause a spongey pedal due to flexing or incorrect mounting. What makes a huge difference is pad material, I suspect
this thread will soon have replies from those who have had similar experiences telling you Mintex M1144 pads are the way to go.
Once that is all sorted out you may find you have to do something to reduce the braking on the rear but that can wait until after the front is
sorted out. Sorting the rear may be as simple as fitting smaller bore rear wheel cylinders.
I had the same thing on my Tiger,albeit with standard M16 calipers.
I put on a MK1 fiesta non servo master cylinder, it has made the feel so much better and I don't need half as much pressure on the pedal.
There is a bit more travel though,definetely worth it!
Wise wortds from BT above.
If that master cylinder is too large a bore the pedal will feel hard and dead. I made that mistake, fitting a 0.75 bore master to a car assuming it
was uprated therefore better. How wrong I was, going back to a .625 and harmony was restored.
I expect moving to a smaller bore will make things far more pleasant.
Mintex M1144 are indeed the way to go, but even then it takes a good 50-100 miles before they start to really bite. Only after a pad change would I consider the master cylinder change. I have just gone thru the new 4pot and mintex route presenting to the IVA and passing the brake test. I had to take for a few short runs (with my foot constantly on the pedal) to get the brake efficiency good enough to pass. The green pads are for frequent track use and will need more pedal pressure but should still be effective. Some with the green stuff get their discs grooved, not sure exactly what the benefit is but one guy I know suggested a better initial bite.
Swapped my green stuff pads for Mintex M1144 pads and the improvement was immediate. try this first.
Thanks guys, some excellent answers here and really helping me shed some light on to the situation. My general thoughts are having read this that it
may well be the master cylinder being too large as the pedal seems quite wooden and not spongy. I may well persevere with the green stuff pads for the
time being just because I think they need to bed in a bit first, but I don't think that that is the real issue.
I do hear what everyone is saying about the Mintex pads and it would certainly be cheaper to swap them over and start playing around with the master
cylinder I'm sure! So that may be the first step, I'm not sure.
So I will check out the threads on master cylinder size and type, is that what most people think will be the problem is?
Thanks again everyone for your help and input.
Second the Mintex pads, they work from cold and are waaay better than the Green Stuff pads, the difference is night and day.
I still have the Sierra master cylinder, I moved the push rod nearer the pedal pivot, that helped a lot, but the Mintex pads made me forget wanting to
change the M/C.
Hi all,
So just pondering responses and thought that I would have a quick look on good old ebay to see if there are any early master cylinders about, and
found this:
FORD FIESTA MK1 BRAKE MASTER CYLINDER ATE UNUSED FINIS CODE 6067715 | eBay
Do people think that this will fit and improve the braking situation?
Thanks again,
Thats the servo version 19 mm bore it will be a big improvement but the ideal is the relatively rare 17.5 mm bore non-servo version.
The standard 2 litre Sierra has either a 22 mm bore with ABS , or 23.8mm bore non ABS.
I've got basically the same setup as you but with mintex 1144 pad and find that I have too much pedal travel, plenty of feel but it feels like I'm about to run out of travel!
Thanks for the replies.
ChrisL - are you saying that you have too much travel but the braking is ok with the Mintex pads? Have you tried to the push rod nearer the pedal
pivot as suggested on here? I will probably do this and change to Mintex pads and see how we go.
Britishtrident - Thanks for your response, much appreciated.
Do you think the one that I sent a link to would be a worthwhile change, along with some mintex pads, or should I hold out and try to find the one
that you suggested. Basically will I see a significant improvement with the ebay one and will it just be slightly better?
Thanks again,
Bare - thanks for your response.
I think you are probably right. I did test drive the car and was told that non servo brakes feel like this, and as I had no experience to compare it
to, I was unsure whether to proceed. I was however explained to, how the IVA tests the brakes so it gave me some confidence, and made me think I would
have a look in to seeing what could be done to improve the performance.
Fortunately there are plenty of nice people giving me the benefit of their experience 
Thanks
Agree with proper survey of cylinder sizes, pedal ratio etc. Just to add my vote for mintex m1144 pads. I had greenstuff previously. They couldn't have been worse if I had painted the discs with grease. After changing them to mintex I could tell braking had increased by about 400% within 200yards of setting off on the first run.
Mintex do have a VERY specific bedding in process.
code:
BEDDING IN MINTEX “M” TYPE MATERIAL M1144 / M1155 / M1166 / M1177 1. Clean discs with brake cleaner or other solvent. 2. Apply 3 to 4 light applications of the brake from 30mph down to 0mph then...... M1144: 6 / 7 steady applications 70mph down to 30mph M1155: 8 / 9 steady applications 90mph down to 30mph M1166: 9 / 10 steady applications 90mph down to 30mph M1177: 9 / 10 steady applications 90mph down to 30mph FINALLY.... Leave to cool as long as possible ( They now work from cold ) NOTE: DONT LEFT FOOT BRAKE ! & DONT LOCK-UP THE BRAKES !
quote:
Originally posted by justy75
Britishtrident - Thanks for your response, much appreciated.
Do you think the one that I sent a link to would be a worthwhile change, along with some mintex pads, or should I hold out and try to find the one that you suggested. Basically will I see a significant improvement with the ebay one and will it just be slightly better?
Thanks again,
To be honest, that's a good guide for bedding ANY brake pad in quickly and properly.
I swapped from a 22mm Sierra mc to a 19mm Fiat one and it made a big difference, so don't discount the 19mm Fiesta mc.
I use standard Sierra brakes with EBC yellow stuff pads [EBC advised me that Green stuff aren't right for a lightweight car].
Stu
Does anybody know whether there is a uprated performance master cylinder that would be a direct replacement AND provide the relevant brake performance
improvement?
Thanks
ok guys, have made some possible progress here. A chap who builds race cars and services high end bits like Ferraris, Astons etc.. had a look at the
master cylinder whilst tuning my webers, and said that it had been plumbed the wrong way, and that the wrong port was going to the wrong brake. Now
although I didnt build it, I am suprised that it would have passed the IVA with it like this.
Can someone please confirm:
Which end of the master cylinder is considered the front - i.e nearest the bulkhead or neares the front of the car?
Which port goes to which brakes?
I just would just like someone else to confirm the correct way the Sierra master cylinder should be connected.
Thanks
Usually the port closest to the pedal end of the cylinder is the front. However, both ports will deliver exactly the same pressure so it won't
make any difference to pedal feel or brake performance (which is why it passed IVA).
I doubt you need to look beyond the reasons given by BT and others. The Sierra master cylinder simply isn't compatible with the pedal ratios
used on most Locosts and having a very hard pedal and poor brakes is a common complaint of those that have used them.
[Edited on 19/7/13 by MikeRJ]
The Sierra MS has 2 ports at the front, these go to the front brakes, and 1 port at the rear, this goes to the rear brakes usually with a
"T" near the back axle.
Fitting the Fiesta MS will only take half a day, you know it makes sense
It really makes no difference the cylinder bore size is the common for both ports therefore the pressure output is the same , switching to a smaller bore cylinder is the simplest way to make the brakes more responsive.
Thanks guys - so what you are saying is that either port should be fine? I think i'l wait until the Fiesta one arrives and just go with that one.
Thanks all for your help - problem solved!
Some feedback on these Fiesta master cylinders
Having purchased one of these and now had it fitted, I thought that I would offer some feedback for others who have or are considering getting a
Fiesta or 19mm master cylinder, as an alternative to the tried and tested Sierra master cylinder.
I originally had a Sierra master cylinder, with HiSpec 4 pots and EBC greenstuff pads. My original feeling was that the level braking was poor. Other
than the exceptionally long stopping distance required to stop the car, it had an incredibly wooden feel to the pedal, with pretty much no feel. It
also took a lot of force to stop the car.
I was aware that the Greenstuff pads were not the best but wanted to try and improve the actual braking before changing the pad compound and getting
the Mintex 1144, as everyone seems to have recommended these as offering a significant improvement over the Greenstuff.
As I couldnt find an early Fiesta non servo master cylinder, I opted for one of these as I was advised that it would be pretty much perfect.
Unfortunately it is not a direct fit as the holes are narrower than the Sierra one so a bracket had to be made.
It is also a bit longer in length than the Sierra one (roughly 1/3" longer). This caused another problem initially as it touched the Webers. By
mounting the bracket behind I was able to make it fit, but beware its a bit longer and may cause a few issues particularly if you are limited for
space in that area.
Was it worth the money and effort? Yes.
Still using the Greenstuff pads the braking has improved maybe somewhere between 80-100%. Stopping distance is definitely shorter and requires far
less pressure to stop the car. The pedal actually has feel now too and does not feel wooden at all. I can actually lock the wheels now too if need be.
Only downside if you call it that is that it seems to have slightly longer travel, with a noticeable first part of the press seemingly not doing
anything, but then the braking kicks in and all is good.
If you are running a Sierra master cylinder and you think that its braking is not up to scratch, then this is Definitely a worthwhile upgrade.
I'm considering this too, good to hear your experiences.
Did you use a servo fiesta master cylinder or did you managed to find a non-servo one?
Also did you need to change any of your pipe work or is it the same as the sierra MC (2 ports at front and 1 at the rear of the MC)?
Thanks.
Oli
Hi,
No I couldnt find an early non-servo Fiesta one, so this was one that originally would have had a servo (The exact version of this mc are in another
post headed Fiesta master cylinders going cheap!)
It does have a couple of extra ports that just needed capping off, but I let a mechanic friend sort out the pipework and the capping.
Forgot to mention that the Sierra reservoir fitted straight on.
Thanks
It may appear that way with Dual cylinders but the pressures are different in use due to the internal pressure passages - the cylinders are typically
marked P and S - P for primary for the Front and S for secondary for the rear.
On my Fury they were installed the wrong way round by the guy that started the car and in testing the rears locked easily - did the research and
re-plumbed - now the front lock up eventually with far better balance.
quote:
Originally posted by britishtrident
It really makes no difference the cylinder bore size is the common for both ports therefore the pressure output is the same , switching to a smaller bore cylinder is the simplest way to make the brakes more responsive.
quote:
Originally posted by Andy S
It may appear that way with Dual cylinders but the pressures are different in use due to the internal pressure passages - the cylinders are typically marked P and S - P for primary for the Front and S for secondary for the rear.
On my Fury they were installed the wrong way round by the guy that started the car and in testing the rears locked easily - did the research and re-plumbed - now the front lock up eventually with far better balance.
quote:
Originally posted by britishtrident
It really makes no difference the cylinder bore size is the common for both ports therefore the pressure output is the same , switching to a smaller bore cylinder is the simplest way to make the brakes more responsive.
quote:
Originally posted by britishtrident
quote:
Originally posted by Andy S
It may appear that way with Dual cylinders but the pressures are different in use due to the internal pressure passages - the cylinders are typically marked P and S - P for primary for the Front and S for secondary for the rear.
On my Fury they were installed the wrong way round by the guy that started the car and in testing the rears locked easily - did the research and re-plumbed - now the front lock up eventually with far better balance.
quote:
Originally posted by britishtrident
It really makes no difference the cylinder bore size is the common for both ports therefore the pressure output is the same , switching to a smaller bore cylinder is the simplest way to make the brakes more responsive.
Sort of ............... The internal passages have no effect on master cylinder output pressure. However a very few (mainly 1970s designed RWD) cars with a front-rear split used a stepped piston in front brake circuit to increase the pressure bias towards the front brakes but these systems are very rare, the only one that I know of that a builder might come across are on some Vauxhall Omegas or Carltons. These days no production cars I know of have a front-rear split system all are diagonal split so cannot use a differential pressure master cylinder.
Quite a few relatively modern FWD cars have 4 ports on the master cylinder with two ouputs lager sized sized threads. The larger sized threaded ports are for the rear brakes and used with pressure regulator valves screwed directly onto the master cylinder body.
quote:
Originally posted by 40inches
But check out the brake balance valve
] quote:
Originally posted by 40inches
As a point of interest, would there be any benefit fitting one of the pressure limiting valves (item 6 in the diagram)to the rear brake line? Assuming they are still available.
Just be aware that with some dual masters there is a definite front and rear circuit connections, They are not the same as there may be no direct
mechanical link from the pedal to the secondary circuit where it is reliant on the pressure developed in the primary circuit to act on the secondary
piston - if there is no pressure in the primary then there is a safety mechanical link present as the back up but in normal operation it is not in
contact with the secondary piston. The pressures are therefore not the same as the pedal is depressed and the port spacing and the internals provide a
timing for the brake actuation. Connect them the wrong way round and you will always lock the back before the front as no pressure can get to the
front until high pressure is developed in the rear.
Just make sure that when you have a cylinder with P and S cast into the body the P is for the front brakes.
This was the type supplied with my 2004 Fury kit
quote:
Originally posted by Andy S
Just be aware that with some dual masters there is a definite front and rear circuit connections, They are not the same as there may be no direct mechanical link from the pedal to the secondary circuit where it is reliant on the pressure developed in the primary circuit to act on the secondary piston - if there is no pressure in the primary then there is a safety mechanical link present as the back up but in normal operation it is not in contact with the secondary piston. The pressures are therefore not the same as the pedal is depressed and the port spacing and the internals provide a timing for the brake actuation. Connect them the wrong way round and you will always lock the back before the front as no pressure can get to the front until high pressure is developed in the rear.
Just make sure that when you have a cylinder with P and S cast into the body the P is for the front brakes.
This was the type supplied with my 2004 Fury kit
I found the best way to bed in a new set of pads was to give the car a good tonking on a trackday
Hi guys, I know this particular problem is now solved, however here's a handy link if you are wondering about master cylinder to caliper piston
ratios and the effects on pedal travel and brake force, even with a brake booster.
www.blackartdynamics.com/BrakeDev/Index.php
Ok you need to know a fair amount of info and there's a lot of information in the results, but there is a pedal input force and pedal travel
display which should give you some idea how well matched your components are!
Hope it is of some use! Unfortunately no input for twin master cylinders though!
[Edited on 20/9/13 by Kozy]
quote:
Originally posted by Andy S
Just be aware that with some dual masters there is a definite front and rear circuit connections, They are not the same as there may be no direct mechanical link from the pedal to the secondary circuit where it is reliant on the pressure developed in the primary circuit to act on the secondary piston - if there is no pressure in the primary then there is a safety mechanical link present as the back up but in normal operation it is not in contact with the secondary piston. The pressures are therefore not the same as the pedal is depressed and the port spacing and the internals provide a timing for the brake actuation. Connect them the wrong way round and you will always lock the back before the front as no pressure can get to the front until high pressure is developed in the rear.
Just make sure that when you have a cylinder with P and S cast into the body the P is for the front brakes.
This was the type supplied with my 2004 Fury kit
quote:
Originally posted by britishtrident.... in normal operation even during initial application the hydraulic pressure in both circuits must be equal at all times.
The pressure in both circuits is equal and rises simultaneously if this were not the case cars with diagonal split brake hydraulics would pull to one side on initial application of the brakes.
Just reading the last 2 posts, and I initially thought the same, however, I think the brake fluid for the fronts will be pushed into the calipers
first, and once they stop moving, the rear cyclinders will move, thus providing a very slight bite on the front brakes befiore the rears? Is this
right?Once ther is no move movement the pressures will be the same in both circuits?
Just my thoughts for discussion.
Regards
Hugh
quote:
Originally posted by hughpinder
Just reading the last 2 posts, and I initially thought the same, however, I think the brake fluid for the fronts will be pushed into the calipers first, and once they stop moving, the rear cyclinders will move, thus providing a very slight bite on the front brakes befiore the rears? Is this right?Once ther is no move movement the pressures will be the same in both circuits?
Just my thoughts for discussion.
Regards
Hugh
If your pedal does nothing for the first inch of travel lengthen the pushrod into the master cylinder, do this in small stages if you get carried away
you will block the fluid return hole causing the brakes to lock on.
Just lengthen so you have a little free movement before the brakes start to operate, when it feels normal
After I fitted the Fiesta master cylinder I had about 20-25mm movement on the pedal, sort of like a two stage after taking up the slack. I bled the
brakes three times and made sure the rear drums self adjusted, didn't make a difference. So I took the drums off to check the adjusters and found
this:
I knew that if the master cylinder was lower than the brakes the fluid could run back, but I assumed that because the fluid reservoir was remote and
well above the MC it was OK, not!
A 10 pound residual pressure valve fitted in the rear brake line, near the MC, cured it and took away the excess play.
I thought rear cylinders had a spring inside them to keep the pistons in contact with the shoes?
At least they do on my ford fiesta rear cylinders 