Sirion Braking Issue / Bleeding

[terios]

Dear all,

My friend bought a Sirion 2nd generation 1.3, 2010, 170000 km.

I've performed a drive test and detected a braking issue: When the ABS activated the brake pads become spongy and go to the floor.

The ABS in my opinion is suspected (or the isolation valves in it) but I decided to try an oil change and bleeding in the hope to chase any possible air trapped in the system.

Changing brake oil lead to a "apparently" the disappearance of the ABS related problem but a new one raised: the pads are now somewhat spongy in the first, say, 3 cm.

Would you please guys help me with your technical advice and workshop manual for that Sirion (especially Brakes sections for bleeding Master cylinder and ABS)

Thx and cheers

[terios]

For info I have used Bosch Dot 4.

[f2ride2001]

Sounds like you still have air in the system.

Suggest to bleed it again or use vacuum feed.

[Sonny06011983]

The workshop manual just describes the standard pumping-method (keep reservoir filled, put transparent hose on bleeder plug and into a container, loosen bleeder and pump pedal, tighten bleeder, release pedal, ....). It doesn't even describe the "professional" workshop method of using the pressurised method.

In the Sirion workshop manual there is no extra content about bleeding the ABS/VSC system (however, i the workshop manual for the Materia, there is. But you need to have access to the Daihatsu DS-II diagnostic tester).

The only solution I could think of is to bleed the brakes again and then drive the car and get the ABS to activate a couple of times (for example hard braking on sand, etc.). Maybe this has to be repeated.

I did replace the brake fluid on a Sirion and on my Materia recently. I've used a cheap vacuum tool and had no problems afterwards.

How much brake fluid did you pump through the system while changing the fluid? I pumped about 0,5l out of every brake, so 2l in total. Did the master cylinder reservoir went empty at some point?

[terios]

f2ride2001, I'll consider to redo the bleeding asap.

Sonny06011983, I did use 2.5 Bosch bottles of 0.25 l each, ie. 0.65 l in total.
And yes in one time during the process I've seen the oil level in the reservoir dropped to the bottom..

In order to bleed the ABS you talked about DS II, is it mandatory or any universal scan tool can do it?


Thank you all for your help, I much appreciate it.

[Sonny06011983]

The DS-II is an OEM diagnostic device. With a simple OBD2-tool you can't access the ABS controller . But bleeding air from the brakes should definetely work without the "bleed mode" of the ABS acutator.

I think the problem was just that the reservoir got too low while pumping, and air got sucked into the system.

You should simply bleed the brake system again. This time with a little bit more fluid per brake, because now we know that air is inside the system. I would bleed at least 0.3l to 0.4l per brake (I always use 2l when changing brake fluid). Just don't let the reservoir get empty again

[terios]

Thanks man i will redo it more carefully and let you know when done :)