| Author | Message | ||
     Brian Vogel Frequent User Username: guyslp Post Number: 71 Registered: 6-2009 |
Hello All, I am facing a situation that I really don't have a clue about what could be going on or how to solve. Last month I performed a "brake pedal test" to get a quick and dirty assessment of the condition of the accumulators. Immediately afterward I developed a leak where the high pressure hose between the pressure switch and the accumulator control valve (ACV) body enters the valve body on system 1 only. It started leaking like a sieve at this connection any time I started the car. I have removed the old hose, checked the bubble flair, cleaned out the seat area and blasted it with canned air, and bought a replacement hose. None of these have worked. Although it's very difficult to get a good visual, what I can see using a mirror doesn't seem to suggest any kind of catastrophic break in the seating area. I also couldn't feel anything weird when using a swab to check for debris. I currently have two ACVs from another car in the process of being rebuilt, and looking at them it seems well-nigh impossible that something could go wrong in the seat area. If anyone has ever seen something like this before, or has suggestions about how to diagnose or solve the actual root problem, I would very much appreciate hearing about it. | ||
| Omar M. Shams Prolific User Username: omar Post Number: 253 Registered: 4-2009 |
From your initial mode of failure the suggestion would have to be a failed hose. When you removed the old hose, did you verify that it had failed? It could be that the new hose was either made poorly or did not seat properly. Focus on the hose and get that completely cleared up before moving on to anything else. Remember - all was well until the system saw pulsations - classic hose failure mechanism. Thanks Omar | ||
| Brian Vogel Frequent User Username: guyslp Post Number: 72 Registered: 6-2009 |
Omar, I have no idea how one would verify that it had failed, barring some very obvious "chunk" out of or dent in the bubble flare. It looked OK, but since I believe it's 30 years old anyway I had new ones made up. I have never encountered a hose failure where it was the flare end where the fitting screws in that failed. I've seen it happen where the fitting crimps on to the hose itself. I've also had leaks before from lack of tightening things down, but don't think that's the case here and don't want to risk crushing the flare by going overboard in the torque department. The new hoses certainly do not appear to be poorly made, in fact, they appear to be of better design than the originals. I shall upload photos. The one in question is the right side one that has a 90-degree angle fitting on one end (which is the end that's leaking, even with the new hose) and a straight fitting on the opposing end. Your assistance and guidance are most appreciated. Brian   | ||
| Omar M. Shams Prolific User Username: omar Post Number: 254 Registered: 4-2009 |
Dear Brian, Your new hose certainly looks nice. I can't tell by looking at it if it is rated for 3000psi - but let us assume that it is for now. If it was me, I would take both hoses back to the shop and ask to have them pressure tested to 3000 psig and watch that they can hold pressure. My money is on your original hose failing the test. The new one may or may not pass but depending on the outcome of the test - you will know what the next move is. You need to eliminate the hose form your fault finding process. I would not be too surprised if one of the crimps on the new hose is imperfect. If your new hose passes the test then ensure you clean the threads at both ends where the hose connects and refit it. | ||
| Brian Vogel Frequent User Username: guyslp Post Number: 73 Registered: 6-2009 |
Omar, The new hoses, picked up yesterday, are all DOT3 rated and pressure tested to a minimum of 3000 PSI upon completion of the fabrication. The shop that makes them could (and would) lose their DOT (Department of Transportation) certification and be subject to some awful penalties if they didn't pressure test each and every hose. Today I already cleaned the threads at the end where the hose connects to the accumulator valve body and have reconnected it - twice. The second time I decided to use some teflon thread tape and it made absolutely no difference. I did not do it at both ends since the straight end fitting was not leaking on either the original hose nor this new one. If doing so would help in any way with diagnosis please let me know and I will disconnect/reconnect that end, too. As it so happens I had two of the right side hoses made as I am working on two different cars that need them. I can try the other if you think that would give you any more data, or I could take the old one from the other car that was OEM and not leaking and see if I can stanch the flow by using it. This issue has me at wits end, since it effectively prevents me from running the car to work on other "revival from the dead" issues as well as putting a really unexpected "monkey wrench" in the works of finishing up the brakes/hydraulics. Brian | ||
| Brian Vogel Frequent User Username: guyslp Post Number: 74 Registered: 6-2009 |
A follow-up to my last follow-up. Today I took off the new hose and replaced it with the old hose from my 1978 Silver Shadow II, which had not been leaking at all on the Shadow. I figured at least it was a good test with the OEM item and known not to leak. Well, I've still got this leak. I am now convinced that this is not a hose issue, per se, but what it is I do not know. It's just impossible for me to believe that three different hoses, one of them brand new, could all leak at precisely the same fitting in precisely the same way if it were the hose at fault. They can't all three be bad. Brian | ||
| David Gore Moderator Username: david_gore Post Number: 1101 Registered: 4-2003 |
Hi Brian, Looks like you now have to look at the accumulator control valve for possible cracks/corrosion/wear/seal failure. The hoses were the logical place to start investigating and you appear to have eliminated them as the problem. | ||
| Brian Vogel Frequent User Username: guyslp Post Number: 75 Registered: 6-2009 |
David, That makes me feel so much better!! (Or not. . .) I had really hoped to be dealing with accumulators and control valves on only *one* car this year!! This is another reason I also wish I had not broken my own general rule and purchased a 32-year-old car that has traveled less than 1,000 miles per year over its lifetime. This is the kind of thing you get from lack of use!! Brian, who actually quite appreciates your input | ||
| Omar M. Shams Prolific User Username: omar Post Number: 255 Registered: 4-2009 |
Dear Brian, You have eliminated the hose - well done. Now the accumulator body. Take it off and give it a good hard look. Good luck. Omar | ||
| Brian Vogel Frequent User Username: guyslp Post Number: 76 Registered: 6-2009 |
Omar, Not that this isn't my next planned step, but if I do find something amiss with the valve body is there any solution other than finding another one? I don't know if the seat can be re-done on this or not. If there is a crack of some sort then I'm definitely SOL. Brian | ||
| Omar M. Shams Prolific User Username: omar Post Number: 256 Registered: 4-2009 |
Dear Brian, The valve body has several o rings. One of them may have popped. They are cheap to replace. Take the Valve body off and give it a good inspection then repalce the o rings and then put it back to see if the problem has been resolved. Good luck Omar |
