Goodridge Brake Hoses

[John Sims]

No John you've also missed it !

The best Pedal "Feel" is Hard, not soft.

No I haven't.

Blade statement that you said was wrong, but then agree with, is that braided hoses give a hard feel compared to the softer feel of rubber hoses. "I've read rubber hoses have a certain amount of 'cushion' " I agreed with Blade7's original statement.

You and I might prefer a hard feel but others might prefer a softer feel.

While a braided hose will ensure the maximum transfer of force it could be argued (and no doubt you will disagree) that the damping effect of a rubber hose gives better breaking application (ie the transition between breaking and not breaking) because it modulates/dampens the transition; the most effective braking being in the shape of a poo.

 

[Diver944]

Well three of the hoses undid quite straight forward after a couple of days soaking in Plus-Gas, but the OSF was a real swine and had to be monstered off with mole grips. Lucky that the hose is being replaced because there is no way you could re use it now. Now the calipers are off I've decided to have them repainted, the plates on the front two had lifted a little as well so now is a good time to remove the corrosion underneath before the repaint.

I didn't realise the rear calipers were actually serviced by hard metal pipes attached to the torsion arm, and the flexible hoses are right at the pivot end of the arm. Who knew???

The hard pipe on the rear nearside looks a little worse for wear, I'd better call Porsche and see if they are still available and how much.

 

[924Srr27l]

No John you've also missed it !
The best Pedal "Feel" is Hard, not soft.

No I haven't.
Blade statement that you said was wrong, but then agree with, is that braided hoses give a hard feel compared to the softer feel of rubber hoses. "I've read rubber hoses have a certain amount of 'cushion' " I agreed with Blade7's original statement.

You and I might prefer a hard feel but others might prefer a softer feel.

While a braided hose will ensure the maximum transfer of force it could be argued (and no doubt you will disagree) that the damping effect of a rubber hose gives better breaking application (ie the transition between breaking and not breaking) because it modulates/dampens the transition; the most effective braking being in the shape of a poo.

It's best if you refer to the two types as a Rubber hose or a Plastic (ptfe) one, it's then"Braided" bit which is only a cover and this may confuse some people. Talking of which it's a very simple analogy and not just my thoughts that if you want the "best" in reference to brakes (In this case) you want them to work as fast and instant as possible.

If as you suggest some people like a spongy soft pedal, then each to their own....BUT in the context of what's best this is 100% not.
The best is a solid metal line all the way if it were possible from cylinders to calipers, a metal tube does not flex as much
as Rubber, and in this thread a (Braided) ptfe plastic hose doesn't flex as much as a rubber hose.

Because the car's suspension rises and falls and the front calipers also turn, flexible hydraulic hoses must be used, but Racers who generally want the best use as hard a flexible hose as possible and also as much hard pipe as possible to eliminate the expansion of the flexible lines. (Otherwise they would use flexible hose for the entire system, but this would be very spongy!)

When a rubber hose expands the fluid is not going forwards and pushing the pistons, it's going sideways! and bulging
the hoses, so to summarise again, what people refer to as Braided hoses improve the brake feel and performance.

I can't think why anyone would want to have a brake pedal that was soft and long which didn't operate the brakes when they need them due to a delay of the hoses bulging?

R

 

[924Srr27l]

I didn't realise the rear calipers were actually serviced by hard metal pipes attached to the torsion arm, and the flexible hoses are right at the pivot end of the arm. Who knew???
The hard pipe on the rear nearside looks a little worse for wear, I'd better call Porsche and see if they are still available and how much.

Yes the minimum amount of flexible lines are used for the best performance, hence why the hard (Metal) line is used from the caliper to the end of the trailing arms and then a relatively short piece of flexible pipe to move with the suspension.

Any decent garage can make up Copper / Nickel pipes if they are not available from Porsche.

R

 

[blade7]

If as you suggest some people like a spongy soft pedal, then each to their own....BUT in the context of what's best this is 100% not.
The best is a solid metal line all the way if it were possible from cylinders to calipers, a metal tube does not flex as much
as Rubber, and in this thread a (Braided) ptfe plastic hose doesn't flex as much as a rubber hose.


When a rubber hose expands the fluid is not going forwards and pushing the pistons, it's going sideways! and bulging
the hoses, so to summarise again, what people refer to as Braided hoses improve the brake feel and performance.

I can't think why anyone would want to have a brake pedal that was soft and long which didn't operate the brakes when they need them due to a delay of the hoses bulging?

R

Do you suffer from dyslexia, or do you just get off on misrepresenting and contradicting people? For a while it seemed like you'd cleared off to bore people on another board, but sadly you're back.

 

[924Srr27l]

I can't think why anyone would want to have a brake pedal that was soft and long which didn't operate the brakes when they need them due to a delay of the hoses bulging?
R

Do you suffer from dyslexia, or do you just get off on misrepresenting and contradicting people? For a while it seemed like you'd cleared off to bore people on another board, but sadly you're back.

No, do you suffer from quoting things so often but never actually explaining your view, and unyet if questioned you prefer to reply with rudeness and not offer any constructive replies?

Thread Number 16
"It's a long time since I've had a car with them fitted, but I've read rubber hoses have a certain amount of 'cushion' and braided hoses can remove some of the feel."

As it's been such a long time there's a strong chance you have no idea what you're talking about, also as you've read something (no doubt on the Internet) there's also a very strong chance it's not correct.

Hence if anyone's gonna correct the nonsense often written on such sources like the net, it'll be me!

Now, about this "Cushion" and feel do your understand soft / cushion / expansion is not ideal when you want your vehicle
to stop? and a harder feel is giving you "More" Feel because it's actually doing something! so how this can (as you say) "Remove it" is a mystery!?

R

 

[blade7]

Hence if anyone's gonna correct the nonsense often written on such sources like the net, it'll be me!

LOL.

 

[Waylander]

The hard pipe on the rear nearside looks a little worse for wear, I'd better call Porsche and see if they are still available and how much.

well depending on what car exactly, the little pipe down the swinging arm is £121.13 upwards, the pipe from the three way spliter to the flexi is £79.00, and genuine flexi hoses are £40 each,

so a complete set of rear hard pipes and hoses from Porsche is not far short of £500

In fact the full length of the car pipe is cheaper than the 18 inches down the swinging arm, wonder who uses a bingo ball mixer to make up the prices

 

[John Sims]

Hence if anyone's gonna correct the nonsense often written on such sources like the net, it'll be me!

LOL.

Happy days.

 

[John Sims]

..... you want them to work as fast and instant as possible.

My point entirely. Unless you have the skill, and are paying attention, to modulate the pedal pressure appropriately "instant" may not be a good thing. Granted ABS does offset the issue because "instant" and "hard" will otherwise result in locking the wheels. This would be bad.

You also conveniently overlook modulus of elasticity. Rubber hoses give, but not infinitely. The amount they give reduces the more pressure is applied. Obviously (because otherwise you will argue the point) there is a margin between the rubber diminishing in its electricity and failing, this is why they don't make brake hoses out of condoms.

It is all a matter of degrees. We aren't all driving gods who drive in bare feet on steel pedals with solid hoses to experience every subtle nuance of the brake pedal. We all have different pedal experiences and preferences, be it different shoes, different brake pads, different brake configurations and different brake hoses.

I am still of the view that vehicle manufactures don't fit braided (ptfe lined, what ever) hoses by default just because of cost but because, in day to day use, the element of damping afforded through rubber hoses is advantageous in most non track situations.

 

[Eldavo]

Hence if anyone's gonna correct the nonsense often written on such sources like the net, it'll be me!

LOL.

Happy days.

Glad it’s not just me John []

 

[924Srr27l]

..... you want them to work as fast and instant as possible.

My point entirely. Unless you have the skill, and are paying attention, to modulate the pedal pressure appropriately "instant" may not be a good thing.

Blimey John ! I'll happily discuss technical terminology, theories and logic but the above statement is a tad far fetched!

Instant may not be a good thing! ?? I'm sure no manufacturer would of built in some delay to the brake actuation because as your suggesting some drivers are not as good as others !

I'm sure you'll remember driving Non servo'd car's which required a lot of leg pressure, in time servo assisted brakes became the norm and benefited all road users (Good and poor skilled drivers) that you don't have to use a lot of force.

Of course rubber hoses and crimped fittings are far cheaper for manufacturers than a stainless steel metal braided ptfe plastic hose, but why does the aftermarket sell thousands of kits, and why do most race cars use them? because if there's a benefit available they want it!

Brakes are a matter of safety for road cars too, and the "press on" driver will benefit from an improved pedal (EG: quicker response / bite and faster retardation)

If for some reason some people prefer a longer and slower to act brake pedal ...each and to their own!

There's also a good case from a cost point of view to fit ptfe hoses and also have copper nickel hard pipes made up which will be a very small fraction of replacing them with Porsche parts.

From Memory the entire car on 924srr27L had brand new copper/nickle hard pipes made up and 4 flexi ptfe lines all costing no more than £200 (to buy and fit)

R

 

[John Sims]

Blimey John ! I'll happily discuss technical terminology, theories and logic but the above statement is a tad far fetched!

Instant may not be a good thing! ?? I'm sure no manufacturer would of built in some delay to the brake actuation because as your suggesting some drivers are not as good as others !

Brakes are a matter of safety for road cars too, and the "press on" driver will benefit from an improved pedal (EG: quicker response / bite and faster retardation)

If for some reason some people prefer a longer and slower to act brake pedal ...each and to their own!

As there is no significant initial pressure change in getting the pads to contact the disc initially the claim that ptfe lined hoses are faster is erroneous.

Following the initial contact phase then I agree a system without damping will have a more linear application. Assuming both systems deliver sufficient pressure to lock the wheels (if ABS wasn't present) then the (possibly) more compliant (rubber hose) system will potentially have a longer pedal travel to take up the possible expansion of the rubber hose when looking to apply ultimate pressure.

My comment is based on the assumption that you don't want to apply ultimate pressure, because the brakes will lock. Brakes aren't a switch; you don't want to apply ultimate pressure instantaneously. So there is a middle ground between no brakes and instantaneous brakes which is the optimum. The optimum brake application (in the considered opinion of people I respect -YMMV) is in the shape of a poo ie the change from none to the required amount is a tapered curve.

I understand the advantages of ptfe lined hoses but I also appreciate there can be advantages in correctly designed rubber hoses on a road car. You seem intent on looking at the absolutes of everything in order to argue against these potential advantages to a road car.

You also have to consider the difference between driving on a track and on the road - even "press on driving on the high way" is completely different to on a track. On a track you go round and round repeating the same thing over and over and doing more and more until you frighten yourself. If you brake too late or too hard you just don't do it next lap. There is almost no situation where you need to do an emergency stop. And you are 110% focused on the job in hand. Driving on the road is nothing like that, when you are minding your own...STOP!!!

I can see both sides, you don't appear to have that capacity.

 

[924Srr27l]

Blimey John !

As there is no significant initial pressure change in getting the pads to contact the disc initially the claim that ptfe lined hoses are faster is erroneous.

Following the initial contact phase then I agree a system without damping will have a more linear application. Assuming both systems deliver sufficient pressure to lock the wheels (if ABS wasn't present) then the (possibly) more compliant (rubber hose) system will potentially have a longer pedal travel to take up the possible expansion of the rubber hose when looking to apply ultimate pressure.

My comment is based on the assumption that you don't want to apply ultimate pressure, because the brakes will lock. Brakes aren't a switch; you don't want to apply ultimate pressure instantaneously. So there is a middle ground between no brakes and instantaneous brakes which is the optimum. The optimum brake application (in the considered opinion of people I respect -YMMV) is in the shape of a poo ie the change from none to the required amount is a tapered curve.

I understand the advantages of ptfe lined hoses but I also appreciate there can be advantages in correctly designed rubber hoses on a road car. You seem intent on looking at the absolutes of everything in order to argue against these potential advantages to a road car.

You also have to consider the difference between driving on a track and on the road - even "press on driving on the high way" is completely different to on a track. On a track you go round and round repeating the same thing over and over and doing more and more until you frighten yourself. If you brake too late or too hard you just don't do it next lap. There is almost no situation where you need to do an emergency stop. And you are 110% focused on the job in hand. Driving on the road is nothing like that, when you are minding your own...STOP!!!

I can see both sides, you don't appear to have that capacity.

Thanks for your views John but the pressure differences and pedal feel are all a worldwide proven test of facts and figures.

This Application, thread and the original OP's question was met with several members approving and claiming they had seen / felt an improvement when fitting Goodridge hoses.

Most of these I believe were for road use, were many Porsche Transaxle lovers change components to gain performance on the road, most of which comes from the track but a lot of items can also reep benefits on the road without having to drive at breakneck speeds where you should be 110% focused at all times.

A view on both sides (Road & Race) would be those that don't want to change any component other than original equipment, and / or those that don't race on the road. A lot of Porsche's on the road drive very slow compared to other trafic.

The front line pressure on a non Brembo caliper 944 is 412psi, with a clamping force of 1460psi and a pedal pressure to lock at 42kg front and 37kg rear. This is information I have to hand as I went through all the stock system, and then had to specify the Wilwwod 6 & 4 Piston calipers and 968 Master cylinder specs which were all being fitted to the 2.7 924 to get the correct front and rear bias and also pedal pressure's.

The Wilwood system pedal pressure required to lock is less than OE, as is the clamping force, because 20 pistons working for you with hydraulic pressure has a lot more torque than the big single piston sliding OE calipers.

This reduction in pedal effort makes the car easier an faster to drive for circuit racing, there is a situation where an Emergency Stop is required for circuit racing which is before almost every corner! this makes for faster laptimes as the speed scrubbed off is done in the shortest time and distance. Any long pedals and / or semi applications of the brakes shows for slow laptimes.

Our data telemetry showed a longitudinal braking force of 1G at last weekends Donington Club Enduro
race, this is higher than most fast cars can corner! If we had OE rubber hoses fitted we'd find it a big disadvantage.

R

 

[944Turbo]

Just a few comments in no particular order
Bert from Berlyn used to advise against goodridge braided hoses on the rear as he had seen some damaged internally, given that most people on the thread seem to be happy with theirs it is possible there have been changes to the construction so I didn't mention it earlier.

I agree with John, a pedal that gave instant pressure to the point of locking up would be extremely hard to modulate.

I believe the Porsche supplied flexis are of very good quality and have a double pipe design, Unless you are comparing new factory flexis (rather than 20 year old ones) against new goodridge it is not really a fair comparison!

I am interested that Roger went for willwood as they used to have a bad reputation for caliper flexing, hopefully that is now improved and the reputation undeserved.

I find it interesting that while shouting down any other views (and using pictures of a race car to 'strengthen' his) Roger may not be aware John S also used to do some racing - arguably in a car better suited to most circuits than any transaxle Porsche

Whilst I agree with Roger that making your own rigid brake pipes is rewarding and inexpensive in his photo above they look more vulnerable to snagging on debris than I remember the factory ones being - It is a while since I have looked under through so apologies if they follow the factory routing!

And back to Paul - excellent, shiny calipers and glad they all came undone in the end!
Tony

 

[John Sims]

.... there is a situation where an Emergency Stop is required for circuit racing which is before almost every corner!....

Well that wasn't my experience but then I'd never claim to be a driving god.

 

[blade7]

.... there is a situation where an Emergency Stop is required for circuit racing which is before almost every corner!....

Well that wasn't my experience but then I'd never claim to be a driving god.

Emergency Stopping before almost every corner gives faster lap times apparently.....

 

[924Srr27l]

Just a few comments in no particular order
Bert from Berlyn used to advise against goodridge braided hoses on the rear as he had seen some damaged internally, given that most people on the thread seem to be happy with theirs it is possible there have been changes to the construction so I didn't mention it earlier.

I agree with John, a pedal that gave instant pressure to the point of locking up would be extremely hard to modulate. Rubbish! Some road car's have a very sharp (Often Over servo'd) brake pedal which will have you out your seat if you press too hard. Others are not so strong and over the years I've probably owned 30+ cars all and every one of them different, and I've adapted accordingly, as I'm sure anyone does and has.

"Locking up" is quite difficult to do if the bias is set properly and as above the driver applies the brakes in a fashion that suits how aggressive the brakes react.

So on a system that has a lot of power and torque, the pedal does not need to be hit hard and if it's also
using as hard and non expandable lines as possible, this makes them even more accurate.

EG : Crap brakes on any car require a lot more pedal effort to make the thing stop, this is more than likely
to cause a lock up as initially naff all much happens but then they wake up and retard but because the said user has had to apply so much pressure they then can lock...

A Pukka system is easier to control, which with multiple stops from 100+ mph again and again and in my Racing case per lap and (in a 2 hour race) is set up to last (With high temp pads & Fluid) and the pedal does not need to be mashed 5 times a lap otherwise it'll get too hot, boil the fluid and offer poor performance.

Here's a picture (At the bottom) of some after market (Zimmerman Sport) Brake discs I used initially for road use and 2 track days which they worked fine, but then the car was changed a lot and the extra grip from downforce and suspension mods made the car work 100% harder. Then these Road discs couldn't cope for this FULL Racing use and they cracked and died!

Horses for courses, Road use is one thing, Fast road another, track days another and lastly a FULL race application on another 5 levels up. I'd say this car would now lap Oulton Park 20 seconds a lap faster than when it was being used as a road car, and this was one that had a higher power to weight than any production transaxle inc 944 turbo's / the 968 & Carerra GT etc...(Not the 968Turbo or S)

I believe the Porsche supplied flexis are of very good quality and have a double pipe design, Unless you are comparing new factory flexis (rather than 20 year old ones) against new goodridge it is not really a fair comparison!
YEs very true, and NEw component OE / standard or even uprated will often perform far better than one that's seen 20 + Summers and winters


I am interested that Roger went for willwood as they used to have a bad reputation for caliper flexing, hopefully that is now improved and the reputation undeserved.
YEs they did, often the lug mounted ones would flex, this happened probably a decade or 2 ago...the radial mounted versions are far stiffer and their subsequent recent lug mounted ones stronger and with bridges..

The Brake discs can move (Side to Side) as they are on floating bolts and the disc / Hub bolt holes are slotted to allow the disc diameter to expand.


I find it interesting that while shouting down any other views (and using pictures of a race car to 'strengthen' his) Roger may not be aware John S also used to do some racing - arguably in a car better suited to most circuits than any transaxle Porsche
I challenge this....924srr27L is to my knowledge now the highest spec fastest lap timed 924 Racecar in the Uk that I know of. What years did you have a competition licence John? ... the 80's -90's?

Whilst I agree with Roger that making your own rigid brake pipes is rewarding and inexpensive in his photo above they look more vulnerable to snagging on debris than I remember the factory ones being - It is a while since I have looked under through so apologies if they follow the factory routing!
They had not been fastened down with clips in this picture........

 

[Eldavo]

"To your knowledge”?

Given the rest of some of your "knowledge" then it’s highly likely you’re wrong again.

Once again we’re on the merry-go-round of you shouting everyone down with the volume of bilge you’re posting, whilst bringing up your car at every opportunity. You’re on a Porsche enthusiasts’ forum - there’s a very very strong chance (to my knowledge) that someone reading the thread will have a faster car, more experience, more money, a bigger house and a fitter wife.

Feel free to tell us (briefly in future please) your own personal experiences but don’t shout down and poo-poo what others are saying just because you don’t agree.

 

[John Sims]

I find it interesting that while shouting down any other views (and using pictures of a race car to 'strengthen' his) Roger may not be aware John S also used to do some racing - arguably in a car better suited to most circuits than any transaxle Porsche
I challenge this....924srr27L is to my knowledge now the highest spec fastest lap timed 924 Racecar in the Uk that I know of. What years did you have a competition licence John? ... the 80's -90's?

Words fail me..