luke_501 Posted April 8, 2011 Share Posted April 8, 2011 hey guys, i went to bleed my brakes and found a leak in my driver side back line. i tried getting it off with a wrench but wasn't workin for me. are these a certain connection that a wrench wont work on or was it just because of the grease buildup? any help would be awesome! thanks Link to comment Share on other sites More sharing options...
Andreas Posted April 8, 2011 Share Posted April 8, 2011 Brake lines are notorious to be very hard to remove, especially if they are old. Two things that worked for me SOMETIMES is a line wrench and lots of PB Blaster. Even then, I had to give up and use Vise Grips on some, which means you will have to replace that line (rounded the nut)... Link to comment Share on other sites More sharing options...
Sam (Bones) Posted April 9, 2011 Share Posted April 9, 2011 sounds like it's time for some new lines. don't takes chances with a brake line, losing your brakes can be hazardous to your health ( and to others on the road too) Link to comment Share on other sites More sharing options...
RichG Posted April 9, 2011 Share Posted April 9, 2011 to Luke_501: In case you didn't know, they make a wrench called a "line" wrench. It is like a box wrench with one flat missing so you get 5 sides on a nut instead of 2 with a regular open end wrench. They are perfect for brake lines. Sometimes you just can't save a line, but a line wrench is your best shot. Sears and many others sell them. Link to comment Share on other sites More sharing options...
PapaCoop60 Posted April 9, 2011 Share Posted April 9, 2011 Luke; I have been working on my brakelines as well. I ended up cutting them off close to the nut and using a 6 point socket. They still rounded and I had to use vise grips. Good luck with your project. I ended up ordering all new lines from Inline Tube in Michigan. They custom bend the lines to fit on your car. They did a very nice job! Link to comment Share on other sites More sharing options...
MGD72Monte Posted April 9, 2011 Share Posted April 9, 2011 I am working on my rear brake lines as well. The line wrenches are a great tool. Otherwise the nuts get rounded off very easily. Once that happens, vise grips are the way to go. Work them back and forth to break the "rust seal". I recommend you disconnect the main rear line (the one coming from the front proportioning valve) at the rear hose. Use a rubber cap to cap the line. That way the master cylinder doesn't drain down you and you only have to bleed the rear lines. Now you can work on the rear system without fluid drip worries. If you have a rust related leak on one of the lines, the other likely also has rust issues. Those are small lines which you can easily replace yourself for a few dollars. While you are in there look at the brake cylinders, also relatively inexpensive to replace if they are leaking. Good luck. Link to comment Share on other sites More sharing options...
cny first gen 71 Posted April 9, 2011 Share Posted April 9, 2011 I did learn a little trick a while back by mistake but it works great. Go to the dollar store and go to the bathroom cleaner isle and get a prodect called the works toilet bowl cleaner its in a white bottle with a blue lable. pour some on the fitting very carefully let it sit for a while then repete. BE CAREFUL NOT TO SPILL ON ANYTHING YOU DONT WANT RUINED this stuff is acid and burns like heck. it will help remove the rust. make sure you rinse it off afterwards and it will eat skin and clothes so be carefull. but its great for removing rust it melts it away. Oh yea it works pretty good on calicum build up on toilets too. Link to comment Share on other sites More sharing options...
Rob Peters Posted April 9, 2011 Share Posted April 9, 2011 Oh yea it works pretty good on calicum build up on toilets too. Sounds like a good Quote Of The Week candidate Rob Link to comment Share on other sites More sharing options...
luke_501 Posted April 9, 2011 Author Share Posted April 9, 2011 thanks guys! after looking over all my lines i decided to go ahead and order new lines for the whole car. i figure there is probably another line bad or about to have problems so i said screw it and just got all new. yeah i knew about the line wrenches but dont have a set. i didn't know how often i would use them so i never got any. i guess i just need to suck it up and get some. sounds like they will save my alot of time and anger. lol Link to comment Share on other sites More sharing options...
KWick_70MC Posted April 10, 2011 Share Posted April 10, 2011 thanks guys! after looking over all my lines i decided to go ahead and order new lines for the whole car. Good call.. Link to comment Share on other sites More sharing options...
luke_501 Posted June 8, 2011 Author Share Posted June 8, 2011 Hey guys, i finally got my brake lines on. and of course i stumbled across another problem. If it went perfectly everyone would rebuild cars i guess. anyway, i am not getting fluid back to the rear drums. I bled them twice and both times i got fluid out in the back. I checked my brakes and im getting no stopping power from rear. when i jack up the rear end and put it in gear the wheels start spinning but when i hit the brake they dont stop. front brakes work fine! 5 years ago when i first got the car i just started ripping everything out in plans to buy new. I took out original brake booster and master cylinder and replaced with new one couple years ago. i dont remember if the original had a proportioning valve coming off the m.c. or not. so i didnt' put one on the new setup. Could this be the problem? With that being said, i have fluid coming out the distribution block on the frame heading towards the rear but it seems like there is not enough pressure. i dont know. Any help would be appreciated! thanks in advance! Link to comment Share on other sites More sharing options...
luke_501 Posted June 8, 2011 Author Share Posted June 8, 2011 my first paragraph was confuzing. Basically what im saying is. first 2 times i bled brakes i had fluid coming out. but rear brakes didn't work. so i went to bled a 3rd time and didn't get any fluid at all. Link to comment Share on other sites More sharing options...
iceman Posted June 8, 2011 Share Posted June 8, 2011 I do believe that the dual master cylinders like our cars have require a proportion valve in order to function properly. Link to comment Share on other sites More sharing options...
luke_501 Posted June 8, 2011 Author Share Posted June 8, 2011 i thought it might, but i took off the original so long ago i couldn't remember! thanks! Link to comment Share on other sites More sharing options...
cny first gen 71 Posted June 9, 2011 Share Posted June 9, 2011 perportion valve is mounted to the frame I belive there may be a button on the end of it thay may need to be pushed in it may require some pressure. If the valve tripped it will do that. That was a real problem on the 80 era gm mid sized cars with 9 inch brakes. Link to comment Share on other sites More sharing options...
LS5 Posted June 9, 2011 Share Posted June 9, 2011 Ok....I have noticed nobody has asked what year the Monte carlo is.???? as 1970 had a proportion valve off the master and 71-72 didnt,and the distribution block is down on the frame by the oil filter area,and in the rear there is a step off valve on the rear cross frame above the rear axle....My money is on that rear Step off valve is Shot...which is more square and about the size of a US Dollar coin. Just my 2 cents worth... Darren. Link to comment Share on other sites More sharing options...
wallaby Posted June 9, 2011 Share Posted June 9, 2011 step off valve? I have never heard of that...I thought that fitting was a simple Tee fitting. Are you saying that fitting has some sort of mechanical function? With your current brake issue, how does the pedal feel? Link to comment Share on other sites More sharing options...
LS5 Posted June 9, 2011 Share Posted June 9, 2011 This what I got from Ground up Restoration and GM here locally, Disc brake hold off valve or step off valve..... "Part Description: This valve was used to hold off pressure to the rear brakes so the front brakes would go on a split second before. This was also considered a correction valve for the 1970 model year. During extreme braking conditions, this valve prevented the car from getting sideways and evened out braking loads (step off). This valve is located at the rear of the car, mounted to the back cross member close to where the rubber brake hose attaches through the frame. Darren. Link to comment Share on other sites More sharing options...
cny first gen 71 Posted June 10, 2011 Share Posted June 10, 2011 Thats a new one to me also Darren thanks im going to have to look at that on mine. See we do learn something every day, Thanks Link to comment Share on other sites More sharing options...
MGD72Monte Posted June 10, 2011 Share Posted June 10, 2011 I just disassembled my rear brake lines and saw no part which could be considered as a step off or any other type of valve in that area. Any pics? Basically I have the main line which comes from the proportioning valve at the front, then connects to a brake hose which has two other connections, one for the line going to the right rear and one going to the left rear brakes. I would recommend looking for a proportioning valve somewhere up front, plenty of fluid in the master cylinder, good condition of lines and adjust the rear brakes. Good luck Link to comment Share on other sites More sharing options...
LS5 Posted June 10, 2011 Share Posted June 10, 2011 Hey MG, I dont have a picture but here is one on an Ebay listing and it shows on a parts list 70 chevelle and 70 monte etc.... Ebay # 200615080921 Link to comment Share on other sites More sharing options...
Mo's70MCs Posted June 10, 2011 Share Posted June 10, 2011 Hey MG, I dont have a picture but here is one on an Ebay listing and it shows on a parts list 70 chevelle and 70 monte etc.... Ebay # 200615080921 Here you go. Link to comment Share on other sites More sharing options...
MGD72Monte Posted June 11, 2011 Share Posted June 11, 2011 Well that's interesting. Like I said, I saw no such thing when I took my system apart but you guys got me curious to examine further because I know my lines were not all original, so I cracked open the 72 Chevelle, El Camino, Monte Carlo Factory Assembly manual and I don't see this anywhere. P. 174 Section 5F Sheet 5 - Rear Brake Pipes is where I would expect to see this but it only shows the items I took off my car. I'm thinking this was not a 72 item. Link to comment Share on other sites More sharing options...
luke_501 Posted June 14, 2011 Author Share Posted June 14, 2011 yeah i do have that step off valve on my car. My car is a 70. so maybe i need that proportioning valve directly off the m.c. I have the one that's on the frame below the m.c. so you guys think it's that step off valve or the possibly missing proportioning valve off the mc? Link to comment Share on other sites More sharing options...
wallaby Posted June 14, 2011 Share Posted June 14, 2011 Here is a little more info from the Year One catalog: http://www.yearone.com/pco/0_1109/full.asp?page=367 It would seem that all is needed is a line going from the master to each brake, but disc and drum type brakes require different pressure levels to get the job done. Drum brakes require lower pressures because they are "self energizing" and drum rotation tries to expand the shoes...disc brakes don't have that advantage, so they need extra pressure to get the same stopping power. That's over-simplified, but you get the idea. It looks as if the models up to 1970 had the proportioning valve near the master cylinder, and 1971 onwards had the valve mounted to the frame. As I understand it, the two valves look different, but do the same job. You don't need both. If that crazy stepoff valve is suspect, you can simply loosen the line going into it, and see if you have brake pressure going into it. Just like bleeding a wheel cylinder. If fluid is going in but not coming out, I'd guess there's a problem with that. LOL Link to comment Share on other sites More sharing options...
Recommended Posts