Residual Pressure Valves (RPV's) -- Help!!

OK ... so here's the deal: Because my M/C is mounted under the floor on the `30 coupe -- and is therefore below the level of calipers (front) and wheel cylinders (rear) -- I bought into the notion that I needed to install residual pressure valves. The whole system has been plumbed but now that I'm trying to charge it with silicone brake fluid, I've got persistent leaks on the pressure valves. (I chose silicon fluid for several reasons, not the least of which is that it won't lift paint.) I've damned near busted a gut tightening fittings, and most of the system is fine, but I can't seem to keep those PPV's from leaking. Any ideas??

 

I had to remove the one on my front brakes because it was keeping the front brakes engaged... I have 2lb residual valves and disc brakes... Mine don't seem to leak though...

 

They might have bubble flares.... I know the adjustable prop. valve I used had them....

 

really?

what brand was the one that caused this?

 

Are the fittings on the residual valve pipe to IFF?

 

RPV's are Wilwood units, 10-lb and 2-lb respectively. Fittings are pretty standard stuff: 3/16" lines, double-flared. And yes, I've checked the flares for burrs, irregularities, etc.
OBTW ... Eastwood's flaring tool ain't real cheap, but it's the shits.

 

Are the fittings on the residual valve pipe threads?

 

They leaked for me as well, wilwood said use teflon tape. I used a master with rpv's built in and shelved their crap.

 

mine leaked too , i just kept tightening and loosening till the flare made 100%contact

 

Good question ... and I don't have good answer. I'm using the same fittings that I used for the remainder of the system build. Am I gonna need to add a 3/8"/24 IFF to 1/8" NPT Adapter? Have I already boogered the threads?

 

Where did the flare adapters that go in the RPVs come from? Are they the ones Wilwood sells for the application? Some OEM adapters will use a slightly different taper on the pipe threads (JSP instead of NPT). I've used these RPVs for years and I've seen that problem before... Just a thought.

 

There are no adapters installed between the line and the RPV? As near as I know they are all pipe and will need a flare adaptor.

 

yep mine needed adapters that came with them ...pipe to flare

 

FWIW, my Wilwood residual valve had pipe threads. I used an adapter to get from 1/8 pipe to IFF for a 3/16ths line, forgot the size but I think the adapter is 7/16ths 24 IFF.

Are the threads buggered up, well you can try some teflon tape on the adapters and tighten them up and check for leaks.

 

Same setup here, waiting on my 2nd 10lb RPV (Wildwood). Mine leaked like hell and I busted the adapter trying to tight it. I will try the teflon tape trick in the reinstall.

 

Best solution.....throw away the Wilwoods and get some brass residuals.....

 

the threads in the Wilwood RPV's are definitely 1/8-27 pipe thread. Never had a leak, the Wilwood adapters even come with thread sealing goo on them.

 

Thanks to all for the help. I think the solution to my problem may be to purchase some IFF to pipe thread adaptors. I'm just sorry that neither Wilwood nor my vendor told me they would be an indispensible part of the installation.

 

like others have said, there should be a valve and two adapters in each kit, Willwood uses a red sealer on the adapters if I remember right. Look at the valve and if you have adapters in it, check if the leak is coming from the flare or the pipe thread. We usually put teflon on the pipe thread as a standard procedure. like others have said it can help to tighten and loosen the flare nut several times to help seat the flare.

 

Wilwood actually sells them both with and without the adapters
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Part Number​

</TD></TR><TR><TD bgColor=#dedfde>2 lb residual pressure valve (blue)</TD><TD bgColor=#dedfde>

260-1874​

</TD></TR><TR><TD bgColor=#c6c3c6>10 lb residual pressure valve (red)</TD><TD bgColor=#c6c3c6>

260-1876​

</TD></TR><TR><TD bgColor=#dedfde>2 lb residual pressure valve (blue) with fittings</TD><TD bgColor=#dedfde>

260-3278​

</TD></TR><TR><TD bgColor=#c6c3c6>10 lb residual pressure valve (red) with fittings</TD><TD bgColor=#c6c3c6>

260-3279​

</TD></TR><TR><TD bgColor=#dedfde>1/8-27 double ended brass fitting</TD><TD bgColor=#dedfde>

220-2415​

</TD></TR><TR><TD bgColor=#c6c3c6>1/8-27 to 3/8-24 tube adapter</TD><TD bgColor=#c6c3c6>

220-4024​

</TD></TR><TR><TD bgColor=#dedfde>Check Valve (black)</TD><TD bgColor=#dedfde>

260-3501​

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OK ... I think you guys have helped me solve the problem. Or at least I hope so. My Wilwood RPV's came WITHOUT the adaptr fittings, and I didn't know any better . I've visually inspected them and I think if I add a pipe thread to IFF adapter at either end of the RPV's my problems will be solved. And I'll add teflon tape on the pipe thread side, thanks to the good advice I've gotten here. Thanks guys ... I'll let you know how it turns out once the adapters are installed.

 

A trip back to the shop confirmed that the Wilwood units are definitely pipe thread. And they came without the adapters. Because the brake line fittings threaded up, I didn't realize that adapters were gonna be needed. But thanks to your help/advice ... parts have been ordered and I'm back on the right track. Thanks again!!

 

I ordered them from Advance Auto, and since removing it haven't had any problems... My MC is under the floor on the frame rail, but is still slightly higher than the calipers on the front... didn't have any problems with the one on the rear, which are disc also... both valves were 2lb...

 

Wilwoods suck, order brass ECI ones. Plus they come with the right adaptors. The Willwoods will crack and leak even with the right fittings. It has been discussed here any times.

 

Be aware that silicon fluid will leak past a fittings threads easier than regular brake fluid.

In fact, if you're running a hydraulic stop light it will fail in a few months because the silicon fluid gets past the seals and somewhat insulates the switch contacts.

Use an external stop light switch.

I know a lot of guys say not to use Teflon tape, but this is one place it works well.

What you don't want to use is LocTite's PFTE thread sealant.
It works, but locks up the fitting so tight that if you try to disassemble it an hour or so after assembly it will many times peel the threads right off an aluminum fitting.
If you do use the stuff, give it 24 hours to set up and it will release easier . . . it'll still be tight, but most of the time will release without damage to the aluminum fittings . . . not always though.

I like LocTite products, but this stuff isn't what you want to use on aluminum.

I like to use Never-Seize on aluminum pipe threads, just don't get carried away with torque or you'll split a fitting.

 

One other one on brake lines.

If you have to use a union to add some length, use a steel one.
Weatherhead makes one and you can also find them on the stockers in the junkyard.
Most common on Fords.

A brass union doesn't want to seat well enough for silicon fluids and I'm guessing the same may be true for regular fluid.

 

Although i have never had a brake switch failure due to Silicone fluid (which i do use) I have heard this legend before. I will tell you that Harley Davidson's have been using Silicone Brake fluid for over 20+ years now and they have in line hydraulic brake light switches. The ones from Harley seem to last a long time. Maybe try using one - Genuine H-D not the Chinese aftermarket ones.

 

That may do it.
Hydraulics are a lot easier to install than the mechanicals.
The brake switch doesn't leak, it's just that the lights won't come on easy like they did at first and eventually you have to apply more foot pressure than is needed for general driving just so the brake lights will light.

I went through a couple of hyd switches from the 'real' parts house about 14 years ago, gave up and swapped to a mechanical switch.

If the Harley switches would do it I'd be tempted.

There are 'low pressure' hyd switches available from the hot rod aftermarket, but I'm told the stock ones only take 7# to close the switch so the low pressure bit may just be a marketing device.

I would guess the HD switch would be close to the same pressure-wise.
They have a 1/8-NPT thread?

I like going to the local HD shop.
Nice folks and some things aren't as expensive as you may think.
Bought a new crash helmet there last fall.
Righteous price, nice helmet.
(My old one was out of date to use at the airport drags.)

Youngest daughter in line at the drags wearing my helmet.

 

Yes the Harley ones are 1/8 Pipe. Like I say, make sure it's a genuine H-D part to be safe.

Word of caution on a motorcycle helmet - motorcycle helmets are tested differently than automotive. Why? In most motorcycle accidents there is a single large impact whereas in most race car accidents there are multiple impacts, especially during rollovers where you are banging your head against the cage for instance. I was a Licensed tech inspector for the SCCA for years and we did not accept "M" rated helmets for racing, only "SA". Something to be aware of.

 

Thats what ya need.. i cant believe you didnt see this? i used teflon tape on my adapters with no problems either..
Dave