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I have had 3 of these Brake Junction Box Leaks leak over the past 15 or so years and my parts cars (2 940s and 1 740) are getting picked over. The 740 had a different ABS and Brake Junction box. I replaced one today and it leaks also. It looks like the top large nut is pressed in and the high pressure and corrosion is more than the main body and large nut can hold. The body and large nut are magnetic, I would guess cast and steel. I wonder if I could clean the junction up and braze the two together without burning out the threads and if there would be any internal damage? I assume there is nothing inside that the heat would hurt.
Here is a picture I submitted back in 2012 of the part (pretty sure it was me):
https://www.brickboard.com/GALLERY/images/10699.jpg
Does anyone have the part number for the Junction box (Spook?)?
Thanks
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Dear jd620,
Hope you're well. Volvo VADIS - a superseded dealer parts/sevice database - shows that for a sedan the "junction" - in Volvoese a "reducing valve" - is #3546634 and for a wagon is #3546635.
Both are NLA, i.e., are "no longer available" from a Volvo dealer.
You should be able to source once from a salvage yard. If the car lived in the desert southwest, the unit should be rust-free.
Hope this helps.
Yours faithfully,
Spook
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Thanks Spook! I'm not sure what I will do. I have limited access to the car. I'll post back with a solution later.
I'm surprised there aren't more brickboard posts about these brake junction box-"reducing valve" leaks.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Dear jd620,
Hope you're well. I recall few - if any other - posts relating to the brake system's "reducing valve". It is mounted on the inner fender wall (driver's side) and not much exposed to the weather.
This part is not "flimsy". Is the corrosion on the fittings or on the valve's body? The valve's body is made from pretty thick steel.
The brake fluid pipes seem to be made a nickel-copper alloy, so corrosion resistant.
I wonder if a former owner - if any - for years failed to flush water-contaminated brake fluid. Brake fluid holds moisture (water), so could corrode the steel valve body.
Hope this helps.
Yours faithfully,
Spook
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Well, this is not one 940 but 7 running and history includes 2 940s I have for parts. The 3 leakers have been on different cars. There are 4 of us driving the 940s many miles in MN, a salt state.
Check out Woody66 post in 2006:
https://www.brickboard.com/RWD/volvo/1116793/940/960/980/V90/S90/leak_brake_junction_box_93_945t.html
If you check out the picture at:
http://www.brickboard.com/GALLERY/images/10699.jpg
and look at where the leak occurs, there is a large nut that is press fit into the body of the assembly. Both metals are ferrous (corrosion). The body appears to be cast iron as in plumbing fittings (coarse texture) and the large nut is smooth texture, probably steel.
I probably should change the brake fluid more often. It was getting dirty in the recent car that had the leaky reducing valve.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Thanks Art Benstein for the picture. I don't know why they should leak where they do on our 940s but I seriously doubt as Blindboy wrote in his reply to an earlier post - "Ive never had this problem,Ithink youre doing something wrong".
It doesn't seem to matter if the valves are rusty or not as to whether they leak. The replacement I put on yesterday had rust where the junction of the large nut and valve body met but after driving it this morning for maybe 30 miles and lots of braking, no leaks.
After replacing the valve back in 2006, I never had another problem with leaks on that 940. I think the leakers were all on 1994 940s - bad batch from ate?
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Dear jd620,
Hope you're well. You've likely nailed it: castings can be porous, i.e., can have pinhole flaws.
This is why galvanized (zinc-plated) steel pipe and fittings (tees, elbows, etc.) aren't to be used for gas supplies (violates most building codes). Pipes/fittings for gas have only a thin layer of black paint (anti-corrosion).
Zinc plating - however thin - can seal a pinhole in the underlying steel. Over time the zinc will oxidize. Zinc oxide (a white, powdery materila) will let gas exit via the pinhole in the steel.
Thus, I suspect some of these brake proportioning valves - that leak - had "thin" spots that - with time and corrosion - produced "pinhole" leaks.
Hope this helps.
Yours faithfully,
Spook
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While checking for more Reducing Value leaks, I came across this:
https://www.brickboard.com/RWD/volvo/1633885/940/960/980/V90/S90/proportion_reducing_valve_leak.html
Not too uncommon!!
Amarin, did you replace the valve or repair the old one? Your post is in the link:
https://www.brickboard.com/RWD/volvo/1634627/940/960/980/V90/S90/proportion_reducing_valve_leak.html
Another mystery-The reducing valves as in the 3546634 has a nut on the bottom and the ones on the 93-95 940 do not, the body of the valve is threaded?
I took the big nut loose on the leaky valve and found an active pressure regulator (spring and brass tube that seals onto a teflon rounded stud). The big nut is actually threaded and the fit of the big nut into the valve body looks like it is with tapered threads.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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I had replaced it with NOS part from local Volvo store in July 2017. No repair kit was found then on any website including my favourite eBay so replacement was the only option. The old valve was leaking - only slightly around the big nut but these later dried out leaving yellow-white crud around it. Brake was working well before replacement. I had to top up fluid every few months interval about 5ml. So it was a very very small leak. After replacement the brakes do work a bit better (subjectively).
Amarin.
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Thanks Amarin for the reply. Do you remember if the bottom connection was directly into the housing or into a nut which was threaded into the bottom housing, same setup as the top connection?
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Bottom connection was NOT directly into the housing. There's a brass port (a brass nut with threaded hole) on the housing into which the bottom brake pipe is connected.
Amarin.
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Thanks again for the replay and the picture.
The original Reducing Valves on all of our 7 940s had the bottom connection directly into the housing and the replacements I have seen have had the brass port (a brass nut with threaded hole) on the housing into which the bottom brake pipe is connected.
I'm wondering if functionally they are the same. Also, there is a number in the casting under the top big nut that is different on each "17G", "20G". Any idea what that means?
Sorry to beat this to death.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Sorry to disappoint, I don't have any info on those castings. Regarding the bottom brass nut it would be interesting if comparison could be made between those two. Just to see if the valve without nut has less restricted opening vs valve with nut.
I can confirm that the valve with nut is type 3 for 4 doors cars (the one installed on my car) whereas the valve without nut is type 2 for 5 doors cars.
This from blue Volvo pocketbook..
Without brass nut (the number 2 is stamped on the raised casting - for 5 doors cars):
https://www.ebay.com/itm/ATE-320120-Rear-Brake-Power-Regulator-Valve-for-VOLVO-740-850-940-960-1983-1998/123663926094?epid=7029732122&hash=item1ccaf1c34e:g:nnEAAOSwJzpcdADQ
With brass nut (type 3 for 4 doors cars - part #3546634):
https://www.ebay.com/itm/Volvo-740-850-940-960-S90-Brake-Hydraulic-Line-Junction-Ate-3546634-NEW-B9/202766646206?epid=1739688949&hash=item2f35d57bbe:g:7jYAAOSwesRdZv0x
Amarin.
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Thanks again Amarin. I have checked all 9 of our 940s (2 are parts cars) and none have/had the bottom nut on the reducing valve. There are 3 1995 sedans, 4 1994 sedans (2 are parts cars), 1 1993 sedan, 1 1993 station wagon.
Your sedan is a 1994 with the bottom nut. Did the original have the the bottom nut?
I believe I have this right:
sedan=4 door=type 3
station wagon=5 door=type 2
I wonder if Volvo used what parts were on hand. The mystery remains!
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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Did the original have the the bottom nut?
--> Yes. The replaced part was identical to the old.
Perhaps you could refer to the number casting on the valve. Is it 3 or 2? In my RHD car the number is facing the tire fender wall (I'm sure it is 3). In LHD it could be read easier. There are only 2 versions of the valve - sedan or wagon (ie 3 or 2). No specific version for RHD or LHD.
Amarin.
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Amarin,
Thanks again. I checked the casting number on all the cars this morning except the car of my daughter's that I replaced the valve.
The casting number was facing the engine and under the large nut as you wrote in your last email. I suspect the casting number was changed on the sand mold periodically when the valves were made. Some were not readable. Here is the car color (for my reference), year, and casting number.
Red 95 - 2
White 93 - 8
Tan 94 (Ohio) - 2 Leaked, replaced
Tan 94 (Mtka) - unreadable
Black 95 - unreadable
Amethyst 95 - 1
Red 94 - 1
Tan Wagon 93 - 5
Also, does your car have ABS? All of ours have ABS.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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No ABS. I have the 940 parts catalogue. Cars with ABS or not both have the valve installed.
Amarin.
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I forgot that some markets didn't get ABS. Here, I believe, every car with ABS splits the two hydraulic circuits between front and back, and every car without ABS had the dual-diagonal split, which required two proportioning (reducing) valves for the rear brakes. Interesting design choice.
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Art Benstein near Baltimore
A bicycle can't stand alone because it is two-tired.
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Thanks Art for the reply. So, do cars without ABS have a Reducing valve with two proportioning valves in the same body, one each for the diagonal split? Then do the ABS cars have just one proportioning valve for the front hydraulic circuit and the rear circuit has no proportioning valve?
I don't think there is an active proportioning valve for the ABS cars lower connection used for the rear brakes (no nut per previous posts) because there would be no way to get the regulator circuit into the casting?
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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The valve adjusts the pressure lower for the rear brakes -- in any car. The front brakes get the full pressure, so whether in ABS cars or not, the valve or valves are for the rear brakes.
I can't speak to the purpose of the nut or its relation to which side of the valve is the reduced side, but the dual diagonal cars have a separate circuit to each of the two rear wheels, so there are two separate reducing valves, located near the rear axle in the cars I'm familiar with.
I think where there's only one circuit feeding both rear brakes, the reducing valve could be located anywhere along that one pipe, so it makes sense to have both distribution (manifold) for the front, and reducing valve in one casting, with one pipe to the rear. Isn't there a tee near the rear axle in your car?
Does anyone here have the green books for brakes late enough to include ABS?
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Art Benstein near Baltimore
She had a boyfriend with a wooden leg, but she broke it off.
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Reading this, my guess that the connections to the front circuit were made for the convenience of using the reducer casting as a manifold was wrong. It is explained as a safety backup for hydraulic failure.
http://borich.lesnoe.spb.ru/auto/Volvo/GreenBooks/TP30838-2_700_brakes_incomplete.pdf
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Art Benstein near Baltimore
The man who fell into an upholstery machine is fully recovered.
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Thanks for the reply and the link (is the .ru link safe?) Art. I wish I could say I fully understood the write-up in the box with the picture. Sometimes I think my old brain is beyond comprehension of such things. Does my interpretation sound right below?
I took the big nut off (the top of the casting) and inside is a seat and needle with a spring which I assume is a pressure regulator. Normally the connection from the upper side connection to the top connection (where the big nut is) is open (rear brakes circuit). I assume this connection closes making the rear brakes inoperable when a high enough pressure is reached in the front wheel circuit (the needle is pushed into the seat closing the top, rear brake circuit) which would be the part stated in Art's post "The reducing valve is independent of the ABS system, it's sole function is to reduce the pressure to the rear wheel circuit under severe braking conditions, to prevent wheel lock". Any fault in the front brake circuit, for example a burst brake line, would mean the pressure would not be available to close the rear brake circuit (pressure regulator would not close the rear circuit) which is maybe the other part of the write-up in Art's post "A built-in safety function connects the valve to the front wheel circuit. In the event of hydraulic failure in the later, this ensures that full, unreduced braking pressure is delivered to the rear wheel circuit".
Still to be determined is the difference between the reducing valves with one big nut on the top end (all of our 940s) and reducing valves with two nuts as in Amarin's 940 reducing valve (without ABS) picture which has nuts on each end.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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"Thanks for the reply and the link (is the .ru link safe?)"
Can't help you with your question about web browsing safety -- you'll have to leave that to your security suite. I thought the same, but then figured the Russian Volvo enthusiast who archived some Volvo literature I don't own may be "safe" from Volvo's lawyers, if they're interested.
Since we're talking about safety, it may help you to know I don't own any vehicles with ABS or airbags. My following distance is normally 2 to 3 seconds which is easily three times what the car behind me uses. That's where the ABS might come in handy.
Can't help you understand the valve construction until, perhaps, I dissect the one I have. But without posting any pics, you are saying it isn't like yours anyway, so I have no incentive to destroy it yet.
However, if you can grab that green book (the dot ru link) perhaps on some other computer you can have everything Volvo cares to divulge about its ABS brakes in 7/9 cars, and then after you understand it, contribute it to the 7/9 FAQ compendium.
Meanwhile, I'll be running a free virus scan on that .pdf for what that's worth.
Whew!
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Art Benstein near Baltimore
"I couldn't believe there were 527,986 bees in the swarm!" Tom recounted.
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Thanks for running the scan Art and the link. I did a download and have it saved on my HD. My virus check found no issues. Good stuff there.
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Mine:3-940s running, 1-740, 2-940 parts, dtrs:4-940s running
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The life partner recently got them a 2015 XC60. I find it wonderfully coddling at times, some other times I find the level of technology grating.
It will automatically brake to reduce the seriousness of an accident (ours doesn't have the active radar to actually prevent the accident). During a panic stop it will take over and apply the maximum amount of brake when you fail to do so. When that kicks in an extra set of brake lights come on. I don't expect to need these features, especially not the airbags and various other pyrotechnic devices, but the level of safety/safety features is quite reassuring and, IMO, worthwhile.
However none of that will affect how I define a safe following distance, the balance on the loan for the XC takes care of that.
-Will
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XC60 / Odyssey
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Hello,
1 of my suppliers has a NOS ATE proportioning valve in stock, but only for the sedan.
Please let me know though my website contact page if you are interested.
http://hiperformanceautoservice.com/contact_us.php
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com
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Ive never had this problem,Ithink youre doing something wrong,
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