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BRAKES - Hydraulic lines and system inquiry


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Does anyone have a brake diagram or can walk me through how the hydraulic brake lines are laid out on my car?
I have noticed a brake leak in-between my exhaust system in the rear of the vehicle im trying to determine if there is a distribution block in that area or just the lines themselves....

(Im being lazy trying to prevent lifting it up and crawling up underneath there today) :)

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There are some people here who have done in-depth brake work lately in the areas. I'll start with some easy things and they will chime in with the details.

There's a hydralic diagram on page 5E2-5 of the 1997 FSM. I'll summarize it, from the master cylinder to the wheels.

There are three major pices of the hydraulic system: the dual master cylinder with power booster, the Brake Pressure Modulator Valve (BPMV), and the calipers/disks on each wheel. Everything goes to the BPMV, which is low in the left front of the car. There is a pump and twelve solenoid-controlled valuves, two accumulators abd two dampers in the BPMV, which has the EBTCM bolted to it. The EBTCM/BPMV assembly do your ABS, TC, and ESC or Stabilitrack, in conjunction with the PCM, with which the EBTCM converses intently during any ABS/TC/ESC operation. GM calls electronic stability control (ESC) Integrated Chassis Control System, or ICCS.

The diagram does not show any brake components between the BPMV and the wheel cylinders on either the front or rear. Some cars have one brake line to the rear with a balancing valve or distribution block, but ICCS needs to control the rear wheels separately so each has its own brake line. Some models have pressure reduction "balancing" valves in the rear brake lines but I don't see those in this diagram.

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-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Did you include the diagram? because i cant see it,......
but ill jack it up and crawl underneath it after I prep tonights dinner...(3 Mushroom spaghetti) - In case you were wondering.

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Jim can you double check me here? There is a bar (like a crossmember bar) right in back of my fuel cell that that has (from what I can see) two lines on it 1 I have no clue what it is but its rubber the other one use to be steel (rusted badly) I believe is a brake line up near front of "crossmember bar" that runs behind fuel tank is where it is leaking (on to fuel cell\tank). Now i cant actually see the line leaking but i see this is where the leak is by having my roommate pump brakes..... Can you double check me that there is a brakeline that runs right behind the fuel cell\tank that runs across the "crossmember bar thing?

Thank You in advance for all your help.

Edited by princess
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on my 96 I did all of the lines. There are 2 to the rear. The left rear has a proportioning valve(square type ) by the rear portion of the subframe on the driver side.

It then runs back.

The right rear has a proportioning valve over the rear suspension.

There are 3 hoses in the rear.

Left rear has 2. the steel line goes into one and then there is a short steel line out that goes to the caliper hose.

The right rear has 1 hose at the end of the line to the caliper hose.

If you are saying it is leaking above the exhaust it is likely the right rear between the ELC compressor and fuel tank. It runs along the swaybar.

If you have to do one you might as well do them both

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Go with rockfangd. I have an FSM but I sold the car over a year ago and can't look under it. Rockfangd has worked on his rear brake lines and knows them well.

Sometimes the brake lines in the rear can rust out eventually. Best to replace all the brake lines in the rear, and also the distribution blocks and proportioning valves.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Thanks. I have been through them thoroughly and insist that they must be done properly.

Note there are 2 different proportioning valves.

up to 96 has a block type valve with a pin that has a rubber cap.

97 has a barrel type without a external pin.

Not sure if they are interchangeable but would be good to know. The block type is more expensive. I was able to reuse mine somehow.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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I would not assume that they are interchangeable. The 1996 and 1997 model years are 99% interchangeable but the suspension components are not, and some brake components seem to be different too. Unless I saw both parts listed in an interchange or update on a GM parts list, I would replace them by part number verified through your VIN.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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exactly.

I can tell you that they are still available.

Another thing about the brake lines I cant stress enough is to inspect the brake lines (all 6) between the unibody and the transmission.

My lines were rotted there and failed unexpectedly. I would never have guessed they were so bad until I pulled them out and they turned to dust.

On my 96 I replaced everything from the master to the abs unit, and from the abs unit to all 4 corners. problem solved

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Its squirting out on to the fuel tank almost dead center of vehicle I couldnt get all the way up underneath there but from what I could "see" looked like just the line in that section......(above crossmember frame bar thingie) the proportioning Valves are the things i was wondering about where there located at.....

Now I have done brakes numerous times but I have never done brake lines so im a littl nervous how hard of a task this is going to be for lil ole me....or should i just let my installer do it?
Example when i replaced the radiator in my 99 taurus I was able to do it however I couldnt get the transmission lines reconncted to the radiator so I ended up having towed from garage to AAMAco for them to do it for $300 Still was cheaper than the $845 everyone else wanted to do the radiator job

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It probably blew at the plastic clip that holds it to the bracket between the rear wheels. that would go to the right rear.

Best recommendation is to just replace all 3 hoses in the rear and re plumb the lines to the back. I use only the koni line low,(nickel).

Best line I have ever worked with. Flares are bubble. Line size is 3/16. New line fittings are highly recommended. Metric.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Thank you Rockfangd.......
now because you obviously have great experience and knowledge in this area... o you think this is a job i should tackle myself or just let me installer\mechanic address it?
Im mechanically inclinded (water pumps, drive belt, thermostats, oil changes etc.) but i have never done brake lines before and i know there simple in disconnecting its just the running, cutting and bending of the lines i dont wanna screw up because i am a perfectionists to my core.

YOUR OPINION

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My completely honest opinion is let someone experienced do it.

Reasons being

You really need a lift to deal with the lines

The line to the left rear is a real headache and the right rear is not much better, There is seriously no friendly hand room in there.

The bracket where the hose to the caliper is nearly impossible to get to to remove the retainer clip.

Brake lines are crucial to being done correctly, they must be flared, bent, routed properly. All reasons why I only use the koni line now.

I have done the lines on both my 96 deville and 97 Seville and both took me about 3.5 hours to complete the rears. But I do this kind of work every day.

If you do decide to do it yourself you will need to get a metric bubble flaring tool kit. A benefit to the bubble flares is that it is much easier to do than any other one. And harder to mess up.

I also suggest that if you do decide to do it experiment with a small section of line flaring it to get a feel for it. You can buy a preflared line to compare.

I would not use preflared lines because it is easier to just cut your own length and flare the ends. It is cheaper also.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Thank you......

I was thinking just that when I was under it like I need a real lift for this..... ill send it to my installer hes one 1.4 miles from my house I can get it there wth the leak.

And trust I wasnt going to take offense to that Im a woman who knows she doesnt know everything and I have my limits i appreciate and respect the honesty...'

Edited by princess
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absolutely. I have full respect for anyone who has a knowledge of their vehicles.

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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$609 to replumb all my brakelines to the rear of the car from the distribution block on back........

sound reasonable???

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That sounds a bit expensive to me. A shop with all the right tools and a proper lift should handle this with relative ease. How much did they estimate for the parts and labor respectively?

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By the "distribution block" did they mean the BPMV in the left front of the car, with the ABS motor on it? Or, did they mean the distribution block back near the rear wheels?

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The front. .....

He specifically stated runing the lunes all the way back from the front.

I apologize I wrote all the specific info down but left in it in my office at work.

It was hus suggestion to replumb the lines that ruN from front to back

because they were rusted I do remember specifically asking for the same type of brake

Line that was suggested earlier. This guy is normally anal retentive about his work

Which is why I go to him when i cannot transport my vehicle to Philadelphia

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I only have experience from my 1988 Eldorado, 1993 STS and my current 2002 STS. But judging from them I would say that they are pretty accessible with a proper lift. He just needs to cut the old ones and make three lines with bubble flares/double flares and an extra joint for the left rear wheel brakes. A couple of hours of labour (4 perhaps?) with the right tools. But he will need a lot of line. I would guess about 10 meters.

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600 is kind of steep. I would expect the lines with fittings, line, and proportioning fittings to be around 400.

But if they get done properly, not sloppy then I say it is worth it to get it done. It feels great to not have to worry about having brakes or not.

Make sure they are not done sloppy. It is just not good business.

especially for that price

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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I DID SPECIFICALLY ASK for the exact lines you specified........

To be honest, crap where I live is generally overly expensive anyway which is why I drive 200 miles go Philadelphia to get most work done. But I only hsd 10-20% brake pedal so he got the job out of necessity. .......

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Excuse typos on my lil phone

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Its fixed.... Cost me $567.42 However there was an issue with the Right Rear brake caliper, the bleeder valve was frozen and woudl not open it finally snapped off so i had him just replace the caliper and do rear brakes so heres the break down.$63 for the line and fittings $12 for brake fluid, Brake Caliper $166.82 - (I think thats a bit pricey but it is what it is), LABOR $241.88 (just for lines) , Labor to replace caliper $48.83
add taxes and hazardous materiasls etc....

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