Joshua Dearman wrote:Hey, Update on the brake drag. I grabbed some pressure gauges and found we do indeed have 10psi residual valves in our Gen 3's , don't know about Gen 2's tho. I went to some local speed shops and they said just like (Pushrods & Nitrous!), 2psi for disc and 10psi for drum. Anyway, I found those damn residual pressure valves......there hiding along the hard bend line just below the drivers side rear bench seat. The interesting thing about this is even if you change the MC you will still have the 10psi in the back since this valve has nothing to do with MC. I've been doing alot of sleuthing around asking questions at speed shops around here and they all said the residual valves can't be run in the MC. Actualy, many cars don't have residual pressure valves and there are only needed for performance brake applications to keep the fluid from rushing back to the MC during decompression.....so I was surprized when I found them on my cavi. I installed the neon calipers and brought them up to pressure while off the car...( a piece of wood substituted for the pads and rotor)....when I let off the brake and removed the wood, much to my surprize the caliper piston was sliding out surprizingly fast. Almost too much to hold back by hand...proved that without replacing the valves, brake drag would be certain. Not much given the emense pressure required to stop, but drag none-the-less.
Anyway, I bought some Disc brake 2psi valves and replaced them and all is good, no slide on the repeat test.
Cahill....check for the valves
Schweet Find Man!! I would never of guessed that they would have been outside of the MC.
Do you have a Brand and Part Number for the new 2 psi valves?
'99 2200 LS CX1 Sport
Joshua Dearman wrote:Hey, Update on the brake drag. I grabbed some pressure gauges and found we do indeed have 10psi residual valves in our Gen 3's , don't know about Gen 2's tho. I went to some local speed shops and they said just like (Pushrods & Nitrous!), 2psi for disc and 10psi for drum. Anyway, I found those damn residual pressure valves......there hiding along the hard bend line just below the drivers side rear bench seat. The interesting thing about this is even if you change the MC you will still have the 10psi in the back since this valve has nothing to do with MC. I've been doing alot of sleuthing around asking questions at speed shops around here and they all said the residual valves can't be run in the MC. Actualy, many cars don't have residual pressure valves and there are only needed for performance brake applications to keep the fluid from rushing back to the MC during decompression.....so I was surprized when I found them on my cavi. I installed the neon calipers and brought them up to pressure while off the car...( a piece of wood substituted for the pads and rotor)....when I let off the brake and removed the wood, much to my surprize the caliper piston was sliding out surprizingly fast. Almost too much to hold back by hand...proved that without replacing the valves, brake drag would be certain. Not much given the emense pressure required to stop, but drag none-the-less.
Anyway, I bought some Disc brake 2psi valves and replaced them and all is good, no slide on the repeat test.
Cahill....check for the valves
2nd gens don't have them. It wouldn't be a problem for me anyways since I ran all new brake lines and switched from split diagonal to split F/R.
All brake systems have an inherent amount of residual pressure, or every time you stepped on the brake, the pedal would travel quite a bit before the pads/shoes actually applied (because of the air gap between them and the rotor/drum). This is the first I've ever heard of resiudal pressure valves only being needed in hi performance apps. I'm guessing the shops you went to were more for sport compacts? (which would stand to reason, since many 50s, 60s and 70s cars, especially ones with front drums, came with them from the factory, and I wouldn't expect a Gen X builder to know that
)
The shop I went to specializes in real race cars....from 650hp circle track nascar wannabees all the way to 600cc mini carts.
They probably think that everything they use is high performance and nothing like it is on the consumer market.
About the part numbers, I will get them off this weekend and post them up....it took some adapters too so i'll have to find my receipt and list all the parts. The valves were pricey tho, like $17.00 each and you need two if you keep ABS since out of the ABS you have left and right rear lines so you would need 1 valve for each line. I guess if you wanted too you could try hooking just 1 up to the MC rear out before the ABS module but I wasn't in the mood......
anymore updates on this on the 3gens, I read the whole post last night and this looks like a very promising idea and i might be willing to attempt it with more info
also pics.
Volumeking333 wrote:anymore updates on this on the 3gens, I read the whole post last night and this looks like a very promising idea and i might be willing to attempt it with more info
also pics.
All the info you could possibly want is in this thread somewhere. Are you looking for something thats not here?
sorry i guess i stated that wrong, i realized alot of the info is here. i meant that i would have to comprehend it better for myself. i haven't taken the time to look at my rear brakes and such in order to do this. so it would be more info for me to look up, not for you to give me
sorry
oh yeah and i'm waiting for part numbers on the valves and adapters
yeah i agree a sticky would be very nice.
2004 Cavalier, 2.2 ecotec, 5spd getrag
do you ever notice that the ones who talk the loudest have the least to talk about?
has anyone ever done a How To on a 3rd gen?
JJ
^^ its all in this thread, read it
I somewhere lost the receipt...so my lazy A** has to stand on my head and crawl under the car to get the numbers or at least look and then compare again a catalog to get the numbers. Anyway....I'm curious, would anyone be interested in a better way to space the rotor from the caliper bracket? I've drawn up a spacer bushing matching the bearing flange. This will allow us to space out where we have plenty of bolt to space and keep as many threads on the lug nut as possible, rather than using washers behind the rotor and loose perfectly good threads on the lugs. The wheel bearing bolts have plenty of clearance to take the required spacer and then some.
Heres a pic to look at.....again, this will go between the bracket and the wheel bearing, causing the same required displacement on only the rotor and will fit into everybodys design since it follows the factory bearing size, no larger.
Picture
I'm going to get a local CNC machining company to cut these and I'm going to get prices shortly, I will be able to do a group purchase and specify thicknesses based on individual requirements if needed. They should be cheap....there not complicated by any means.
Good idea. It was on my list of options and I canned it. The biggest reason- I didn't have enough time to get it machined. The next biggest- while test fitting the bearing into the caliper bracket, I got pretty frustrated holding the bolt with a Torx driver and lining up the bearing and caliper bracket to each other and the axle all at once. Adding another item in there just didn't interest me at the time. I guess its not too big of a deal though, since you only really have to do it once, or if the bearing goes, twice. Third reason- the bolts were just long enough to get the nut past the end, but the overall thickness of the spacer only needs to be about .160", so it may be ok. Again, I ran out of time to try different bolts, etc. I'm not sure how long 3rd gen bolts are, but I bet they're the same (typical GM).
I'm happy to see other ideas coming out!
Well.....unless someone proves i don't remember very well I thought the bolts went almost .5" past the nut.
They do with the J body backing plate, but the Neon caliper bracket is thicker (at least 2-3 times as thick). It will work for sure, but you may need to use longer bolts to get enough thread contact for the nuts.
Good point....don't remember looking at the bolt once the kit was installed.
doesn't Cavalier LS comes with rear disc brakes?
I don't know about 1st Gens, But 2nd and 3rd Gens have never come with disc brakes.
cavi's didn't maybe the Cimmeron (sp) you could ask Event about that one but i don't think so.
Joshua Dearman wrote:The shop I went to specializes in real race cars....from 650hp circle track nascar wannabees all the way to 600cc mini carts.
They probably think that everything they use is high performance and nothing like it is on the consumer market.
About the part numbers, I will get them off this weekend and post them up....it took some adapters too so i'll have to find my receipt and list all the parts. The valves were pricey tho, like $17.00 each and you need two if you keep ABS since out of the ABS you have left and right rear lines so you would need 1 valve for each line. I guess if you wanted too you could try hooking just 1 up to the MC rear out before the ABS module but I wasn't in the mood......
Hi friend, do you have more info about the residual valves? pics of it location? pics of it? codes of the 2psi and 10psi units? where other places could be bought? how do you feel your car with the new 2psi valves compared with the 10psi old ones? brake power? drag?
Comments and pics are welcome.
Thanks,
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Hello,
OK....I got all the info and pics. This weekend I even got the ebrake hardware on the 3rd gen using stock cables.
Start from the top:
Heres the pic of the stock RPV(residual pressure valves):
ResidualPressureValves.jpg
I used 2 psi Wilwood valves, part number: 260-1874
You can see from the pic that it has fittings on both ends. This fitting is a #3 flare to 1/8" NPT adapter and is an XRP part number 981603.
XRP 981603
The straight end fits goes into the RPV(pipe thread) and the flare end is the brake line thread.
Now you have a RPV with standard Male brake line fittings on both ends. Only one problem.....the cars original RPVs are female fittings. Now many of you are thinking why didn't I just search XRP's site and find a 1/8" NPT to Female #3AN fitting. Although this might exist....the stock RPVs have two different size male fittings on both sides of the brake line. The upstream is probably 7/16" and the downstream is 5/16 I do believe. I found it easier to cut the original fittings off and buy a pipe flaring tool from Harbor Freight Tools....my favorite store!!!
Flaring tool
This kit also comes with a pipe cutter that works great that isn't shown in the kit.
Once you have the original fittings cut each side, next you side on the brake line XRP's part number 981803 (#3AN female nut):
XRP981803
Now slide onto the brake line XRP part number 981903 (Nut sleeve)
XRP981903
This nut sleeve will snug up to the end of the brake line once the end of it is flared. Then the female nut will slide back to the end and get caught on the ridge of the nut sleeve. Now you should have the assembled brake line with the RPV installed like the picture seen earlier above:
Wilwood Pressure Valve
Now this assembly is a little shorter than the stock valves however you can pull some slack from the rear end to make up the difference pretty easily. I went on step further and just replaced the line all the back from the RPVs.
Heres some pics of the valves installed:
Pic1
Pic2
All those wet spots are brake fluid in case anyone is wondering why I roll with a leaking fuel tank.
I will continue this post to include all the brake line mods....as if this post isn't long yet.
Heres a pic of the full assembled brake line before I installed it.
I installed a piece of crapy line on the other end of the RPV...ignore this...that line is just a representation of the stock line that I will bolt the RPV too.
Also....on that note...I would like to say...don’t be afraid to practice with the pipe flange tool...you aren't crimping the fittings onto the line, just sliding them on and the bolts holds everything tight. So you can practice seating the nut sleeves and nuts on the brake line all you want without consuming the fittings.
O.K., In this picture you can see in the top right my coil of brake line. Then to the left is the tube cutter and flaring tool stuff. Also there is my pipe bender to the right of the flaring tool stuff. Below that is the caliper that once looked clean and bright red.
Now on the caliper I used a 7/16" nut to #3AN Male flare nut, XRP part number 402833
XRP Part 402833
This allows the stainless steel braided brake line to be installed, XPR part number 630036
XRP 630036
I used 36" flexible lines to replace the brake line all the way from the start of the stock rubber flex line into the caliper. 30" would be more appropriate but whatever.
Next on the other end of the flex hose you see a union flare nut, XRP Part number 981503
XRP981503
Then from here I used another nut sleeve and flare nut.
Here's the BOM for the whole brake line job, both sides:
All XRP parts.
(6)
981803
(6)
981903
(4)
981603
(2)
981503
(2)
630036
(2)
402833
(2) Wilwood 2psi RPVs PN: 260-1874
P.S. All of these pics I found online from a site and they look like they have been squished. So when you find the parts in your hand don't think they aren't right just cause they don't look exactly the same.
I will post later about the brake job on the gen3. This post is long enough.
Nice work!
The only issue I see is that you used a 42 degree (SAE) flare tool to make a 37 degree (AN) flare. On a high pressure system like this, its going to leak at some point. If I were you, i would pick up an AN flare tool and reflare the lines to 37 degrees, but thats just me.
That was my concern as well....we will see....I asked around alot before I used the 42 and the response from all the brake shops says I won't have any problems......maybe I'm too trusting. If it leaks it won't be hard to reflare seeing as how everything is nut coupled anyway.
