DIY: 98 V70 Brake Hydraulic Overhaul (Hoses, Seals, Parking)

[QuirkySwede]

- The "good side", i.e. LF caliper, I rebuilt it anyway using ATE seal kit as written in this thread.
During the rebuilt, I got "lazy" and did not want to run the air compressor, so:
* Clamped the brake hose (used card board as cushion).

I would never clamp a brake hose that I intended to use. If it was a hose I was going to cut and toss before the vehicle ever came off the stand, sure, but I would NOT intentionally introduce sharp radius bends in to a vital piece of safety equipment (no different than not letting a caliper hang by the hose, IMHO) merely to avoid loosing some $8 brake fluid. The risk-vs.-benefit is not viable for me.

To give some idea of what happens, look at happens when a section of hose (left) is clamped (right). Both have the same circumference for the I.D. of the inner hose and thickness for the inner and outer. By clamping it the outer has to span almost two and a half times that of the inner (3/1.23) which means the inner gets compressed while the outer is stretched. This is why folding or pinching garden hoses kills the so easily and leads to leaks at the points of most concentrated flex, but they do not have to stop a 3,000 lb vehicle.

Neither I nor any brake hose will last forever, but that doesn't mean I care to hasten either's destiny!

ClampedHose.JPG (30.22 KiB) Viewed 2437 times

For anyone interested, the following have some photos of brake hose construction:
http://www.brakehoses.org/brake-hose/ru ... -hose.html
http://www.brakehose.co.za/hosespipes/cef_rubberbrakehosespec.html
http://www.brakehoses.org/brake-hose/hy ... -hose.html

[cn90]

...I would never clamp a brake hose that I intended to use. If it was a hose I was going to cut and toss before the vehicle ever came off the stand, sure, but I would NOT intentionally introduce sharp radius bends in to a vital piece of safety equipment (no different than not letting a caliper hang by the hose, IMHO) merely to avoid loosing some $8 brake fluid. The risk-vs.-benefit is not viable for me....

FYI,

You are probably new in the car repair business, anyway...

1. The idea is not to save $8 of brake fluid, but rather to avoid running the hydraulic system dry, introducing air into the ABS module, requiring a trip to dealer to "cycle" the ABS module.

2. Bending the garden hose is a bad idea because it introduces a 180-degree (not 90-degree) bend.

3. Also, FYI clamping fuel hose or brake hose with proper technique is taught in professional mechanic schools.
- It is even published in Honda, Volvo technical manuals for the mechanics.
- This is why auto parts store sells clamps especially designed for clamping fuel hose etc.

The idea is:
- Use a cushion material such as old rubber hose or cardboard to prevent "exterior" damage.
- Then GENTLY clamp it down just a touch, only enough to stop the fluid flow.

I have been clamping fuel hose, coolant hose, brake hose for 25 years, zero problems.

Your thought about clamping hose is valid and sounds good in theory. In the real world, it is irrelevant.

[QuirkySwede]

You are probably new in the car repair business, anyway...

Hardly. A person who can't make a point without a personal attack doesn't have one.

2. Bending the garden hose is a bad idea because it introduces a 180-degree (not 90-degree) bend.

That's confusing a longitudinal bend with a radial one. Review the picture. The 90 degree is the sample but it making the hose wall go through a zero-radius 180-turn (90+90=180), and the ratio is the same.
21 / 17 = 10.5 / 8.5, and 6 / 2 = 3 / 1. Nothing's changed.
If this makes it easier for you...

ClampedHose2.JPG (29.16 KiB) Viewed 2439 times

I have been clamping fuel hose, coolant hose, brake hose for 25 years, zero problems.

As a friend once said, "I don't care if you've been peeing behind the couch for 25 years. Doesn't make it right." Same "25 years" argument has also been used to validate smoking cigarettes, and longer durations for the world being flat.

It's not something I would put forth as a DIY method considering this forum is focused on cars that have been out of production for a dozen years or so, thus most are going to have similarly aged (more brittle) hoses. Further, there are many types of hoses or lines (sic) that this method would damage though they appear to be "just rubber" on the outside.

[cn90]

Actually, no personal attack at all. In fact, you criticized a technique that has been used by professional mechanics for years.

Your posts show that you are new to car repair.

Your posts point out to people your inexperience.

Visit any professional mechanic shops in your city and you will see they have hose clamps in their tool boxes to shut off fuel hose, coolant hose, or brake hose for the respective repair job.

Professional technical manuals published by Honda, BMW, Volvo clearly state that one can clamp the hose(s) with appropriate tools/techniques.

Rubber (EPDM) is designed to be flexible, to be bent, twisted thousands of times before they fail.

PS: that hose in my car is brand-new brake hose.

Also, if you had done a google search on "pinch tool", you will see products made to shut the hose:

https://mercedessource.com/node/9376

[QuirkySwede]

Your posts show that you are new to car repair.
Your posts point out to people your inexperience.

Incorrect, cn90, they do no such thing, and they are hardly an adequate sample size to validate such a claim about a person you know next to nothing about.

Preferring not to use a certain tool or practice (for reasons stated) is not the same thing as not knowing about it. Many mechanics and DIYers will sand off gasket remnants, but someone interested in keeping tolerances (e.g. machinist) would not.

If everyone on here did what auto makers advised, the whole injector would be replaced when only its o-ring had failed. Doing a job right and doing it fast aren't always the same thing.

[xHeart]

Such details in discussion makes MVS a very special place for many of us, DIYers and professionals alike.

I stripped the 7mm guide pin last night, it was the last pin to come off, now rounded. It was time to close the day.

Before calling off the day, I left it with PB blaster. I will slice off and remove the rubber cushion, propane torch the bracket for a minute where pin is screwed, and then put a vise-grip to it after filing the teeth on vise-grip.

It has 22 ft-lb torque, not sure about the thread locker, visible rust.

I do have rotary cutting tool at hand, if civil method fails.

[xHeart]

The removal of caliper from the rubber hose, after it breaks loose, requires close to 6 full rotation of caliper for it to come off, and screwed back on without twisting the hose, and for the rubber hose to keep its arch like form.

The vise-grip worked on the guide pin.

stripped 7mm guide pin removal with vise-grip

MVS_0998.jpg (950.88 KiB) Viewed 2431 times

[xHeart]

Two photos after the caliper replacement, rubber hoses...

driver's rubber hose 1/4 turn over twisted

MVS_1002.jpg (1.19 MiB) Viewed 2423 times

passenger's rubber hose arch is good

MVS_1000.jpg (1.09 MiB) Viewed 2423 times

[xHeart]

Next step - brake bleeding. Would this MityVac vacuum instruction work since there isn't a 2nd person to assist.

MityVac Brake Bleeding

[xHeart]

Solo Method: Pump to above 15 inches of Mercury (in-Hg), opened the bleed value 1/2 turn - 180º. 30 seconds of air bubbles, then let it drip close to 2oz, each wheel, while keeping the reservoir filled close to Max marker.

using vacuum to bleed - Solo method

MVS_1005.jpg (837.07 KiB) Viewed 1933 times