just converted drums -> disc, have a problem

[nivit0]

I drove up to Trans Am Creations, bought their drum to disc conversion. Had it installed at a local garage, with mixed results. The garage is telling me the back brakes aren't getting enough fluid now. TACreations tells me the proportioning is done in the ABS unit, and they've never had to change anthing before. The garage didn't make new rear metal brake lines, they just twisted my old drum lines to take up some of the excess slack. Did any of you who have done the swap require any additional parts besides:

Calipers, pads, rotors, e-brake cables, and mounting brackets?

It does feel like the front brakes are doing more of the work than they should, especially at higher speeds. The pedal is nice and firm at low speeds, but has more travel before you really feel it start to engage the brakes at speeds around 40mph or higher. It could be the bias is wrong, could be bled wrong at the shop, or could be a bend was made in the brake line too sharp. Anyone have any thoughts?

There's another issue with them too, I'll go into detail with that later.

[hockeyman]

Sounds like you need to rebuild the calipers. They may be binding up on you, and need to be reagreased. Over the years, the caliper pistons become corroded and rusted, and need to be rebuilt. Also, try re-bleeding the rear brakes yourself, and get all new fluid in there. The garage may not have done it right.
I replaced my drums with disks and I never had to touch the proportioning valve.

-Marc

[Turbo V6 Camaro]

ALSO GET THE RIGHT BREAK LINES!!!!!!!

the "twist" may be "pinching off" some fluid..

[MustangEater8251]

YOu can try this suggestion but I doubt it will work, bleed the piss out of them over and over...

I thought I had mine done, the rears diddn't work, I bled them again, and gott a little more air out after I had driven a little... then tried to rebleed them...

test drove still worked like crap, I blead them agian, found more air....

did this like 4-5 times, then bam they worked, I bled them one more time, had a teenie bit of air in the line, and then I was good.


Of course I had an entire rear axle swap, so I used rear disc hard brakelines, but the stock proportioning valve.

I am not sure if this is your problem, but somehting I expereinced... I mean I swore, I had all the air out of the lines but I guess I didn't. I am sure your shop will argue with you on it, because it makes them look stupid if they cannot bleed brakes [img]smile.gif[/img]

[nivit0]

I'm trying to get the right lines, but that's not easy. The shop I had it done at can't make them, and couldn't order them. TA Creations doesn't sell them. The dealership doesn't sell them. The five parts store chains I called only sell them in pre made 20" and 30" lengths. I bought a pair of 30" lengths, and the shop wasn't able to bend them neatly in the shape needed. I'm considering going to the dealership to have new ones made up right. I'm more than willing to listen if anyone knows where to buy stock disc lines in good shape.

[markV6]

Did you put 93-97 or 98-02 rear brakes?
If you have 98-02 you can always get new lines from GMpartsdirect: LH- PN:10289429 and RH-PN:10289430. Both are total of 9.08$

[markV6]

If you have the 93-97 - my bets bet is - get a double flaring tool kit and new pipes and practice your flaring.

[nivit0]

I got the 93-97 rear calipers. A flaring tool isn't a bad idea, but I'm not certain I want to attempt something as important as brakes without already having the experience. If I tune something wrong on the engine, my motor blows, but I'm ok. If I mess up my brakes, my engine might get to walk away, but I'm dead. One of my goals is to outlive my engine. That's why I'm actually letting a shop do this work, I do most of my own work otherwise.

[markV6]

Well then try to get some old ones from a junk yard i guess

[markV6]

Anyway, here is a link of How-to in case you decide to do your own flares:

http://www.stu-offroad.com/misc/ft-1.htm

[Loochy88]

you do not need the proportioning valve. i just did this swap a week ago. first of all make sure they put the brakes on the correct side of the car. first time through i had my calipers on backwards, theyre impossible to bleed that way. the weights should be on the bottom. take mustangeater's advice and bleed them to death (i went through 3 big bottles of fluid). get a hanes manual and follow it to the T! do every step in there for bleeding several times. thats what my problem was. also ask the shop if they remembered to take measurements to find out if they needed to use gm shim # 12471185, if they give you a puzzled look then they probably didnt use it. i highly doubt that the lines are so bent that they cant get fluid through them. you could really just look at them and see if theyre bent too hard or at two much of an angle. if you bleed them and you can get fluid through fairly easily, then thats not your problem. you probably dont need to go wasting your money on new brake lines, since they only thing they'll do is look "cleaner".

[ March 22, 2004, 11:07 PM: Message edited by: Loochy88 ]

[MustangEater8251]

Originally posted by markV6:
Well then try to get some old ones from a junk yard i guess

Right there...

Go to tacreations in person, and offer a guy $20 to let you take some off a rear end sitting around.

All my dealings with them were ghetto, so they are probably ghetto enough to let you do that.

[nivit0]

I've been on the phone with TA Creations pretty frequently since the swap. They don't have any brake lines from my years. They offered me a set of lines off a 98+ for free, but I don't have the time to go up to Hialeah for a set of lines that aren't made for my car anyhow. The later years put their calipers forward of the axle I think, the opposite of where mine go.

[silvachris1]

You may have the calipers on the wrong side of the car. Since the shop installed them, they may have installed them wrong. I mean like, the right caliper is on the left side of the car, and vice versa. It does make a difference man. Check it out and see if the bleeder plugs would be any higher from the ground if they were flipped over. If so, they're on the wrong sides and holding extra air. I removed my calipers to paint them, and accidentally installed them back on the wrong sides, and could not get any pressure on the bake brakes. Got to looking at them, and realized my mistake, so I switched sides, and the problem went away. Something to look at man, it could be that simple.

[nivit0]

Went back to the shop today with some ideas, and we found the problem. The driver's side caliper bracket (the swing arm) must be bent. I had already replaced one of the caliper pins, but that didn't completely correct it. TA Creations sold me a bent caliper. The inner pad on that rotor was gripping correctly, but the other pad was grabbing at an angle, and only the edge of the pad away from the wheel center was grabbing. Because of that, the piston isn't really finding any leverage. It presses outward, but never really compresses the two pads against the rotor. Most calipers don't come with the swing arm, but my parts store found me the stuff I need. A place in Orlando is sending down a new swing arm and caliper, for $25 and $45 respectively. If this doesn't fix it all completely, then I'll replace the lines, but this was a glaringly obvious mistake.