robtrout5

Being new to the forum and having gained a fair bit of answers to my issues I thought i might post this thread for others to benefit by.

The thought also occurred to me that there is a potential safety issue here where some vehicles with similar configuration may be on the road with only one rear drum brake functioning properly and be unware of it.

Background.

This car is for my son to drive. Its now over 13 years old so with our winter in Canada the brake lines and fuel lines were corroded to the point of being mash.

So in the process of replacing the entire braking system up to the point of the proportioning valve, we had to naturally replace the fluid at some point.

The Honda service manual tells you the sequence and there is good reason for this but it does not elaborate in a couple of areas.

Well we got the new lines in and all connected up and put fluid through all the brake points. In this case we did not think of the bleeding merely filling the lines and the new caliper and wheel cyclinders with fluid.

The problem is in the process of doing this one is essentially "bleeding the brakes".

So when we came to do our bit and "bleed the brakes" according to the sequence, we now discovered no fluid coming out of the right rear brake which is the first bleeding point in terms of the Honda sequence. It also logically happens to be the furtherest point from the master cylinder.

Not knowing what had happened we went back and forth checking and rechecking everything we had done and taking the new brake lines off one step as a time heading towards the master cylinder.

Well we concluded that there was an fault in the proportioning valve. So got one from the local scrap yard for $35 and replaced the vehicle one.

But still no luck and in fact the replacement one was not exhibiting the same "set" condition.

Searching forums and web did no good as issue is not mentioned anywhere.

Solution was to reset the proporting valve. Way to do this can be done a couple of ways. Easiest is to find some 3 inch long solid steel needle thick enough to enter through the hole in the top of the proportioning valve and strong enough to push down on the metal plunger and reset the rubber diaphragm washer inside the valve.

An alternative is to make up or purchase a piece of 3/16 brake line with metric connectors on and purchase two union couplers. Remove the feed line from the ABS where it enters the proportioning valve and couple up to it with your made up line using one of the unions and the line connectors (Canadian tire has them already made up in short lengths with metric connectors if you need one) and then bend it and insert it in the top of the proportioning valve where the line to the right rear brake exits. Now push on the brake pedal and it will reset the valve by pushing fluid back against it.

Then remove the whole contraption replace the lines in the proper places and tighten them up.

Note keep making sure to top up that master cylinder.

Now before you try to bleed the rear right drum brake again, attach a piece of pipe and jar with fluid in to the left front disc caliper. Open the bleed nipple on the left front caliper and let the fluid flow freely. Yeah you gonna waste fluid but there is no other way.

Now go and bleed the rear brake cyclinder while this front nipple is open.

Bleed it sufficient to get the air that was trapped at the valve when you reconnected the line to it, out through the rear nipple.

The secret is by taking the pressure off the proportioning valve through having the front bleed nipple open, the brake fluid can get through to the rear line without the proportioning valve thinking the line is broken and setting to protect you from fluid loss.

So for those of you who have the same config my advice is check that you have both drums properly working next time you got your car on jacks. You may find you have a set proportioning valve and dont know it. There is no switch as they used to have in the old days. Value engineering has done away with good devices like that.

Hope this helps someone out there baffled by how to effect the fix to the proportioning valve after changing their brake lines.