ICP brake cylinders w/ Beringer brakes

[Pat]

Hi,

 

my Sav was converted from bycicle brake lever to pedal brakes. The pedals and cylinders are from ICP. The brake pressure regulator and actual brakes are from Beringer. 

 

The brakes aren't working correctly. I can brake once or twice, but then the cylinders stay compressed and don't come back up and brake pressure is lost. 

 

When I pull the pedals/cylinders back by hand, I can brake again. 

 

I noticed that Beringer cylinders have springs. 

 

Maybe the beringer "anti lock" regulator thinks the brake pressure exerted by the ICP cylinders is too big, and then relieves pressure. And it requires cylinders witj springs to reset so that a new brake application exerts pressure again? 

 

I could try to remove the Beringer pressure regulator part and see if the ICP cylinders come back then (have enough counter pressure)? 

 

Or maybe ICP cylinders and Beringer simply

don't work together at all? 

 

Curious for your take on this! Thanks!

[skippydiesel]

Hi Pat,

• What is the purpose/function of the brake regulator in your system?
• Given that you can reset the system by pulling up the master cylinders, is there any reason why you can't fit springs to encourage the cylinders to return to the ready position?😈

[Thruster88]

The brake master cylinders at the pedal has to have a spring, usually internal to work correctly. The brake pressure regulator IMHO is an unnecessary part / complication on a simple light aircraft.  

[Pat]

12 hours ago, skippydiesel said:

• What is the purpose/function of the brake regulator in your system?
• Given that you can reset the system by pulling up the master cylinders, is there any reason why you can't fit springs to encourage the cylinders to return to the ready position?😈

From here

https://www.aopa.org/news-and-media/all-news/2010/august/04/beringer-offers-low-cost-anti-lock-brake-system

 

The company’s ALIR system, or anti-lock regulator, is an inexpensive approach to an anti-lock braking system for pilots of smaller aircraft.

The $200 in-line device simply maxes out the pressure that a pilot can put on the braking system. By knowing the locking pressure of the aircraft’s brake system, the user can stomp on the brakes as hard as they like and not lock them up. The device also compensates for uneven braking pressure, delivering a constant pressure to both brakes, and decreasing the likelihood of going off the runway because of unequal pressure.

 

 

Regarding the springs it seems the ICP and in general all master cylinders always have springs, some outside and some internally. Maybe these springs aren't strong enough to counter the pedals back to the origin position or maybe the pedals create some over center lock position?! 

[Underwood]

That regulator seems like a waste of money to me.

Firstly the claim to provide Anti Lock simply by placing a pressure limit is Bogus, It can only work for one specific combination of ground friction, tyre pressure and weight on wheel, anything outside of that one set of parameters and you are either going to lock the brake or not be able to exert maximum braking force.

True anti lock that works in all situations needs a wheel speed sensor.

Secondly the other feature of balancing both brake's pressure is a negative one if you want to lock one side to turn sharp.

 

An odd contraption

 

P.S. your symptoms could be the result of leaking internal piston seals, unusual for both to fail the same though unless the wrong brake fluid was used which can wreck some seals

 

 

Edited Saturday at 05:34 PM by Underwood

[IBob]

5 hours ago, Underwood said:

 

 

P.S. your symptoms could be the result of leaking internal piston seals, unusual for both to fail the same though unless the wrong brake fluid was used which can wreck some seals

 

 

The ICP brakes in my build specifically called for mineral based fluid, not synthetic.

[Pat]

On 10/5/2025 at 7:29 PM, Underwood said:

your symptoms could be the result of leaking internal piston seals, unusual for both to fail the same though unless the wrong brake fluid was used which can wreck some seals

Thanks. Would this suspicion still hold true if

A) I was able to apply full brakes once or twice before losing pressure and brakes failing again?
Maybe like this: Brakes applied, pressure builds up, however seals are failed due to wrong fluid, and that's why pressure quickly dissipates again? 

or 

B) if seals are wrecked, I wouldn't be able to build up any pressure at all in the first place? 

[Pat]

22 hours ago, IBob said:

The ICP brakes in my build specifically called for mineral based fluid, not synthetic.

I think I have DOT4 (at least that weird Beringer regulator calls for DOT4). Maybe the master cylinder seals are bad and the system simply can't hold any pressure, but pushing the pedals/master cylinders builds up pressure for a short time?! 

[IBob]

I have the standard ICP brakes.
There is no appreciable 'give' in the pedals at all.
I can't speak for the regulator or how that behaves, but assuming the system is full of oil (?) it seems very likely that the seals in the master cylinders are failing.
My manual says in bold caps WE RECOMMEND THE USE OF MINERAL BASED OIL (DO NOT USE SYNTHETIC OIL TYPE  DOT4).
Or that's what it says after you translate from the ItEnglish that appears too often in the manual.............)

[Thruster88]

Pat, have you bleed the system from the wheel cylinders up using a syringe or pressure bottle? Suck all the fluid out of the reservoir then pump in to the wheel cylinders til no more air bubbles apear in the reservoir. 

 

The beringer valve, which I would remove, may have a shuttle valve in it to do what it does so it may have different requirements for bleeding.

 

Need to use the correct fluid as others have said, most aircraft use hydraulic OIL not brake fluid. If the Orings have swollen from incorrect fluid it may be causing the master cylinder to not return fully. 

[facthunter]

Time to check the condition of the Cups in the Cylinders me thinks and make sure they suit the Oil you use. I recommend the Red oil (Mineral). The other is corrosive and only needed when the brakes reach a high temperature.  Nev

[facthunter]

Disc pads don't move far  back off the discs or there's a lot of pedal travel before the brakes apply. Nev

[Pat]

Thanks all, I will report back when I know more.