brake fluid replacement

[sgupta]

Hi,

I'm relatively new to this servicing but can anyone guide me or point me as to how to drain and bleed the brake fluid from my nissan sentra 1997.

I have got a pump to be used for this purpose but am not sure how to find the bleeders near the tires (does the car need to be jacked up) or just sucking the fluid in the master cylinder is enough.

Thanks,subh.

[nametakennow]

Bleed at all the corners. Speedbleeders make this a lot easier. The bleeders are also hard to get to with the wheels on given that they're on the calipers.

Attach a tube to each one and pump the brake to drain them (one at a time, though I suppose if you had the whole car up you could do all 4 if you're careful about not running the master dry) while adding new fluid via the reservoir. The first one will take longer than the others since you'll also be draining the reservoir through it.

[sgupta]

Thanks. I will try this out today.

[sgupta]

Hi,

I tried this out today. However, I have got a problem now.

It seems when the car is turned OFF, the brakes are hard and not touching the floor but when the engine is turned ON, the brakes become really mushy and soft and touch the floor resulting in no braking at all.

We have checked all the four brake lines for air in the lines and at the bleeder points, all of them seem to be right with no breaking columns of brake oil coming out from the bleeders when the brake is pressed.

There was a mistake for the first time though when I drained the oil. I ended up emptying the reservoir (or the main brake fluid cylinder) and I guess that has caused some air to enter initially, but after that we did a few more rounds of draining the fluid and bleeding it as mentioned and we haven't found any air trapped bubbles in the lines.

Any suggestions on this!

thanks,subh.

[nametakennow]

In essence, your brakes are getting mushy wants they're powered.

My guess is air in the master cyl. I'm not exactly sure how you'd get it out, though. Maybe try that pump you mentioned in your initial post and see if you can get the air bubble?

Also, the master cyl isn't supposed to go dry. If you pumped the brakes while it was empty you may have caused damage.

[sgupta]

I got a speedbleeder from a nearby schucks and repeated the entire step . Its a little soft still but I have done a test ride and am taking it on interstate in another few hours. So far it looks fine.

The only problem I have with the one-way brake hose speed-bleeders is that its hard to fit on the bleeder and spills oil on the insides of the brake and on the axles.

However, I'm happy that the brakes are working and I'm on to my next project.

Thanks for your help, Subh.