Brake Bleeding problem

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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roger lee
Posts: 685
Joined: Tue Dec 08, 2009 11:47 am
Location: Tucson, Az. Ryan Airfield (KRYN)

Re: Brake Bleeding problem

Postby roger lee » Wed May 11, 2016 2:20 pm

Hi BVrianh,

The key here is to open the bleeder at least 2 turns to get a good FAST flow and to have the reservoir open so it flows the same way. The CTSW has the same humped lines under the seat. I have never seen any air bubbles left in any line.

I usually flush each side, Then pump the hand or toe brakes fast and hard about 10 times. This usually moves any air bubble. Then I flush once more. I don't get any air bubbles. The key to a good easy flush is fluid volume and speed. With volume and speed the air is swept away and can not stay static in one place. Use a hand operated oil pump or something with a small volume and slow speed and the air bubbles just work around the fluid and don't get flushed down stream..
Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)

TailTouch
Posts: 2
Joined: Sat May 14, 2016 4:47 pm

Re: Brake Bleeding problem

Postby TailTouch » Sun May 15, 2016 5:18 pm

Roger-
Can you share the Gobosh brake bleed procedure with us.
We've been trying to do this without avail for over 4 weeks now. Had to replace the manifold due to corrosion and a few master cylinders.
It's a PITA with the Gobosh setup.

Thanks.


roger lee wrote:Whose brakes are they. There are different ways to bleed some brakes. The most common for most brake systems is from the bottom up. There are a couple of brake systems out there that take a special procedure and there is no written documentation to do it. The Gobosh is one of them.

Most systems should be bled from the nipple on the bottom of the caliper. The fluid is then pressurized up through the system into the reservoir.
The best and cheapest tool to do this can be had from Ace hardware. It is a 1 gal. pump up bug sprayer. Take off the front nozzle and just slide on some tubing. Pour the fluid in the pump, pump it up and attach the tube to the bottom of the caliper nipple. Then open the nipple on the caliper a couple of turns, press the trigger on the pump and the high speed fluid flow will flush out all air and charge the syste, Put an empty water bottle with a tube on it up on the reservior to catch the over flow. I usually waste maybe 1 ounce. The high speed flush carries air out. Using a slow hand operated oil can is too slow and many times leaves air in the system. The Ace pump is a bout $10 and well worth the money. I can bleed brakes in a few minutes this way. Give me an email address and I can send you a couple of pictures.

let me know whose brakes they are and I may be able to help.

roger lee
Posts: 685
Joined: Tue Dec 08, 2009 11:47 am
Location: Tucson, Az. Ryan Airfield (KRYN)

Re: Brake Bleeding problem

Postby roger lee » Mon May 16, 2016 8:26 am

Hi TailTouch,

The first problem with Gobosh brakes is the company used fuel hose for brake lines using corrosive Dot 4 fluid. (Idiots) That ate them up and caused a huge build up in every component in the system. The last one I did we stripped the entire system. Tore apart the 4 master cylinders to clean them and the calipers. All brake lines were replaced with real brake line. I must have cleaned out over a shot glass worth of decentagraded hose from all the components. My first Gobosh brake job was a 17 hr. ordeal. The cleaning was a pain, but the bleeding was a bigger one. Now I have the procedure down. This is not a brake bleed procedure that any have done and there is no published procedures. Why they set it up this way I'll never know.

There is too much to list here in this job and I'm sure you'll have questions. Please feel free to call me and I's sure I can help.

520-574-1080 in Tucson, AZ
Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)


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