D1 Pressure Reducing Valve Replacement

Casey Pontes

Casey Pontes

Well-known member
Mar 24, 2019
54
7
Utah
Spent a good number of hours 4wheeling yesterday only to discover that the pressure reducing valve on my 1998 D1 is leaking a lot of brake fluid. Just ordered a new ABS compatible PRV. Is the job as simple as removing/replacing the PRV, bleeding the system (all 4 wheels) via conventional brake-petal modulation bleeding techniques, then test driving the vehicle? Do I need to worry about air rising into the master cylinder and therefore rendering it necessary to bench-bleed the master cylinder?

Also, in the future, if I decide to remove the ABS module, will I need a non-ABS compatible PRV, or can I just T the lines at the appropriate place and utilize the ABS compatible PRV I just purchased?

Thanks!
 
p m

p m

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Staff member
Apr 19, 2004
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La Jolla, CA
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Mine was stuck, cutting off fluid flow to the rear wheels. I took it out, apart, and put it back together. Don't remember if I used any specific parts to do it, though.

Yes, the job is a simple as that. You can make your life easier if you have line end caps at hand (again, don't remember the size - close to 3/8"), so once you disconnect the line you cap the end immediately, so not much air gets into the line. I didn't have to bleed the m/c.
 
Frobisher

Frobisher

Well-known member
Dec 27, 2012
202
69
Pennsylvania
I just replaced my proportioning valve* a few weeks back; it's remarkable how much it really affects your braking! I ended up not needing to bleed the brakes. A little extra plastic wrap under the brake fluid reservoir to keep a tight vacuum above, and I was good to go. I'm not sure why I didn't need the bleed, but I'd read it was possible to get away without it, so I test drove locally and carefully, and voila!

The hardest part was securing it to the fender wall since the hole had rusted out a bit more than I realized. Go figure.

*Thanks robertf.
 
Last edited:
Frobisher

Frobisher

Well-known member
Dec 27, 2012
202
69
Pennsylvania
Right. I thought something seemed wrong when I typed that out in response. I should have caught that before I added my two sense. Or perhaps, my nonsense. Good catch!
 
D

discostew

Well-known member
Sep 14, 2010
7,733
1,024
Northern Illinois
Casey Pontes said:
Spent a good number of hours 4wheeling yesterday only to discover that the pressure reducing valve on my 1998 D1 is leaking a lot of brake fluid. Just ordered a new ABS compatible PRV. Is the job as simple as removing/replacing the PRV, bleeding the system (all 4 wheels) via conventional brake-petal modulation bleeding techniques, then test driving the vehicle? Do I need to worry about air rising into the master cylinder and therefore rendering it necessary to bench-bleed the master cylinder?

Also, in the future, if I decide to remove the ABS module, will I need a non-ABS compatible PRV, or can I just T the lines at the appropriate place and utilize the ABS compatible PRV I just purchased?

Thanks!
Click to expand...
Where is it leaking from? Could it be one of the lines attached to it? I think the biggest problem your going to have is rusted brake lines. Replacements from Rover are usually pretty reasonable and come pre bent with fittings already in place.
 
Casey Pontes

Casey Pontes

Well-known member
Mar 24, 2019
54
7
Utah
Got the job done yesterday. The brake fluid took its toll on the brake lines, so the protective coating on the lines has begun peeling off. Going to coat the lines in fluid film (unless someone recommends me not to) to hold them over until a future brake job allows me to replace the lines.

Thanks for your guys' input. For the record, it took nearly 64oz of brake fluid. Before loosening every brake line leading into the PRV, as well as before bleeding each brake, I topped up the reservoir. Thanks, Peter, for the recommendation to plug each brake line... I purchased a set of silicon plugs on Amazon for the job.

Now, onto the new engine and trans mounts I just purchased from Safari Gard...
 
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