more air in n/s calipers than o/s

[wemorgan]

Not a Merc but my Civic, sorry. But this should be generic enough for all cars.

Whilst bleeding the brakes this morning I saw that there was x10 as much air in both n/s calipers than the o/s. The rear n/s caliper looked like a sodastream for a couple of minutes. In total I still only needed 500ml to flush the system.

Q: Is having more air on one side a symptom of something or just normal business. For info. the brakes were last done 2 years ago by a a garage.

Thanks.

 

[Dieselman]

There shouldn't be any air in the braking system. Have you noticed spongy brakes?

 

[wemorgan]

There shouldn't be any air in the braking system. Have you noticed spongy brakes?

Yes they were a bit soft, but the ABS was still able to be engaged if needed. The Civic is known to have a soft pedal anyway, so I dismissed it as being just that. As you'd expect the brakes are quite a but better now.

I'm curious to know why there was so much air in the system and pretty much only on the n/s

 

[Dieselman]

It sounds like the reservoir was allowed to run low during the last fluid change, or the master cylinder is drawing in air.

 

[wemorgan]

Thinking about this a little more. I used a vacuum kit for the first time. It's also possible that the pressure in the hose around the nipple, if not sealed 100%, could also draw in air down the bleed hose.

 

[E55BOF]

It certainly is....

 

[Dieselman]

Thinking about this a little more. I used a vacuum kit for the first time. It's also possible that the pressure in the hose around the nipple, if not sealed 100%, could also draw in air down the bleed hose.

More likely, the bleed nipple threads.

 

[brucemillar]

Dieselman's point is very valid. I would suggest that you check for air again before too long. Just in case..

 

[tonyc280]

I always use a pressure bleeding kit. Far better than a vacuum one !!!

 

[wemorgan]

I always use a pressure bleeding kit. Far better than a vacuum one !!!

That's not an option on the Civic, due to the non-standard sized reservoir cap and it's location 1/2 under the screen cowl. I'm sure Honda have a clever tool in their garage put it limits the DIY-er who can't convince his wife to sit in the car on a freezing Sunday morning pumping the brake pedal.

 

[paul_c]

Yeah I've had issues with vacuum brake bleeding too. In theory its supposed to be quicker/easier, but in practice it seems to not work that well. There's a bit of a knack to bleeding brakes, use whatever you like that puts pressure INTO the brake hydraulics, but don't open the bleed valve too much otherwise it lets air in at some point.