Hello,

Problem:
A Honda Accord 1995 (4-cyl 2.2L, LX) I'm working on has sinking brakes that appear to be a Master Cylinder seal issue since the fluid levels aren't going down.

Observation: It occurs only on hot days but even this is uncertain as it doesn't always occur on hot days. Once it occurs there is no guarantee it will occur again. Some 90+ degree days I can drive without experiencing the issue. On mild or cold days it never occurs.

History: The car is greater than a decade old and the MC has never been replaced. The fluids may not have been replaced as adequately as they should have been. Wheel cylinders were replaced in tandem due to (leaking). Air was most definitely introduced into the brake system for X number of years the WC was leaking. Brakes were bled but the problem persists. At this point I think the long periods of driving with air in the lines caused moisture in the brake system and maybe rust in the MC which damaged the seals.

I'm all but certain this is an MC issue. I plan on doing the replacement myself. I have a few questions:

1) After replacing it, is there a way to determine if installation was done correctly? Trying to avoid thinking that it was correct and then the brakes completely die while driving two weeks later. I plan on following the Haynes manual and Tegger's FAQ.

2) Certain replacements have different bore sizes. Google can give me no answer on what this actually does and whether this presents a compatibility issue. I ordered an MC with a bore size of 0.9375 = 15/16.

3) The MC I ordered has some exceptions in the Fit Notes, it states "With Rear Drum Brake, Nissin Cylinder". Because AutoPartsWarehouse states that the item is compatible I dismissed it but I am starting to suspect this may cause a compatibility issue. If so I can return it and order another, I am uncertain as to what those fit notes may be referring to because it's rather cryptic (short).

Ordered this MC: BF12335
If that one isn't compatible, I'm considering ordering this one: RAYMC39882 (Raybestos).

4) Are there any emergency objections to a Bendix MC as opposed to a Raybestos MC in terms of quality? This is an old car so I don't want to sink a massive amount of funds into this issue. I suspect someone is going to tell me to go $200.00 OEM MC or go home. I just want it to be safe without sinking money into it, I also suspect someone will think this is contradictory as cheap junk can't guarantee safety. I'll hear anything anyone has to say.

 

I think that there was a larger bore size on master cylinder for the EX accords. I am not sure which one you ordered.

The aftermarket MC probably have new seals and springs installed inside and maybe they hone the cylinder walls to ensure they are smooth. I really don't know the quality of the aftermarket rebuilds.

 

Since LX has rear drum brakes, it sounds like you ordered the correct one.

 

If I bench bleed the Master Cylinder, do I have to bleed at each wheel?

Furthermore, since I've drove the car after the wheel cylinders were replaced and the brakes bled and the sinking happened afterwards, doesn't this mean there is air in the lines and the system has to be bled again anyway?

Or can the sinking happen without air in the lines just because the seals on the MC are damaged?

 

If your brakes were fine after you first blend them, then it is unlikely air got into them. To be safe, I would bleed the lines.

Google trotrlIG2sk

It is a YouTube video from ericthecarguy showing how to replace the MC and bench bleed the new one.

 

The booster push rod to MC clearance can be an issue for an aftermarket MC. If the design is different, there may be a chance of push rod not fully relaxing when brakes are released and as fluid warms from driving, the brakes will bind.

Adjusting this gap requires a special tool and under-dash operation that is not fun.

For this reason I bought OEM MC to have maximum chance of not having to readjust. It worked for me. If design of MC is identical this may not be an issue, but something to consider.

good luck

 

Just make sure the booster push rods on the new and old MC are the same length. I would bleed the lines again. You will probably get some air in the lines at the connections to the Master Cylinder.

 

Alright but is it absolutely necessary to bleed at the wheels? I've been reading that it might be possible to get away with it. I might not be able to get the wheels of if they're locked in.

If air were in the lines would I notice it right away or could it hide and emerge later on?

 

As long as you properly bench bleed the master cylinder, you will know right away if there is air in the lines. The brake pedal will feel spongy.

Bleeding each line isn't too bad of a job. Just spray PB Blaster on the bleeder valve, because they can get corroded in place.