I am at a loss on my 88 CRX Si.
I have been dealing with the issue of my drivers side caliper building preassure as I drive.
I have replaced the flex hose to the caliper, the caliper, turned the rotors, and had the fluid flushed.
I have replaced all the pads and one rear wheel cylinder also.

I am not losing any fluid accept when i have to break th bleader loose to release the pressure.

I removed the master cylinder and power booster today and noticed the power booster looks like the master cylinder has been leaking at some point.
I plan to replace the master, but hate to replace the power booster if it is good.

I recently bought the car after it sat for two years and have had the problem since. Any info that anyone may have would be great. Thanks

 

ive heard of this before, but i dont know the answer.

id look into the booster. next thing to check is the check valve. you can also just disconnect the vacuum too, see if that is the problem.

take the MC out again and make sure youve only got one grommet seal behind it.

lastly, http://www.norcalcrx.org/tyson/pics/braketest.jpg

please give us your results. id like to hear the answer to this once its figured out.

 

I did remove the booster vacuum line and start the car. there is plenty vacuum

 

im sure theres vacuum. thats not what i was asking to be checked or tested...

 

sounds familiar.
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/brake-problem-help-2938280/

 

not real familiar with the honda brake system but this will work for any car. When your brake locks up, Break the lines loose at the master cylinder, if you get pressurized fluid shooting out then your master cylinder is locking up, this is probably not the case as you say only one of the fronts is doing it and the forward line on the master cylinder is for both.

Then follow the lines from your master cylinder and find where the front ones tee off, break the line loose on the caliper side there, if you have pressurized fluid there, then the tee is clogged. If the fluid just drizzles out then keep going.

Follow the lines all the way to the caliper and break them loose until you find what is holding pressure on the caliper.

 

Could be slightly clogged up hard line. If it was me I would just dump all the brake fluid and test the hard lines with a air compressor. Did you replace the caliper with a new caliper or used caliper?