brake line

Jack mutters: 1993 Corolla 7A-FE (1.8 L), 265 000 km

Your expert opinion is invited:

Brake fluid is leaking in the centre underbody area. The line(s) are covered by the plastic strip (with oval holes in it).

Is this brake line one-piece from the master cylinder to the area back of the gas tank? Or, are there couplings so that a shorter section can be replaced?

Is this line metric, and are replacement lengths available in southern Ontario? Will I need to buy a bender and flaring tool?

Thanks for taking the time to comment on this, Jack.

Reply to
Ralph
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Brake lines themselves rarely leak unless the fluid is very old and has absorved a lot of water. More likely, a coupling or rubber seal is leaking somewhere and it is following the tubing to the lowest spot. Check the master cylinder or ABS actuator for leaks.

Brake lines are one continuous piece, with no couplings from component to component and pieces should never be spliced or coupled.

Yes and yes.

Will I need to buy a bender and flaring tool?

You will need a tubing cutter, a bender, and a flare tool. Some auto part stores rent tools so you can check on rentals before you buy.

While you are in brake repair mode, I would completely flush out the old brake fluid and replace with fresh fluid.

Reply to
Ray O

-good stuff snipped-

I suggest using double-flared replacement tubing rather than DYI. A single flare may be adequate but I personally do not like 'adequate' brakes.

Proper-sized crow's-feet should be used instead of open-end wrenches when working with compression fittings. A bleeder wrench will also make life easier.

regards A.G.

Reply to
Registered User

Jack updates:

I've removed the plastic channel cover and the brake lines are now visible. Both are extremely corroded at the bend where they go up from under the floor pan to the gas tank well area. One leaks, and the other is probably about to go. (Next it will be the gas line.)

It looks like replacing the entire line one-piece means lots of work in a hard-to-access area of the firewall, undoing flare nuts from the proportioner fitting (or whatever that little block with the lines coming out of it is called) as well as making lots bends.

You've said to use one-piece line: Most of the (hard to get at) front end of the brake line looks like new because it is protected by the engine compartment and covers. Would it be a great crime to cut and flare the existing line at an accessible point under the front of the car, and attach replacement line from there? This would add one fitting to the system. It would perhaps save lots of work.

Thanks for your advice and comments,

Jack.

Reply to
Ralph

I wouldn't consider it a crime to splice the brake line but then I'm not an attorney or law enforcement person ;-)

The conventional wisdom is that one should not splice brake lines, probably because of the potential for a leak. To be honest, I do not have experience with splicing a brake line so I do not know if it will leak or not in the real world.

Reply to
Ray O

Check with the dealer - they do make pre-bent lines as replacements, but they can be either very expensive (shipping is a big chunk of that because it takes a big box and lots of padding) or take a long time to get shipped, or be discontinued because "the car is too old".

This is a 93 Corolla, so they shouldn't try the "too old" argument quite yet. But price out a factory part first, you may be in for a pleasant surprise - it might be cheaper in the long run versus buying a generic straight length of tubing, the special bender, and all the labor you'll invest to pull the old line and then sit there duplicating all the twists and turns before installing the finished product.

Consider that the hydraulic brake system runs north of 1,000 PSI depending on whether it's a normal stop or panic smash-the-pedal. You want as few potential trouble spots as possible - you CAN cut and re-flare the tubing, and put in a double female flare coupling, but that also gives you another failure point. And KISS counts here.

Same thing with the fuel line on an EFI car - they are between 50 and 100 PSI fed from the pump inside the fuel tank, and leaking fuel has the added hazard that it burns quite well, too, especially when sprayed out a hole and forms a nice mist... Takes the whole car out. Get a replacement section of steel line for that also while you're under there fixing leaks.

Personally, I have nothing against cutting and coupling to repair a brake or fuel line, but AFTER you've exhausted all other options. It's not good form, and if the work isn't done absolutely perfect you're leaving yourself open for huge problems.

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Reply to
Bruce L. Bergman

Since it is an older car, and the rear brakes don't really do much of the braking on a front wheel drive car, and it is a duel braking system, if it were mine I'd do the splice. Steel lines are hard to flare but if it doesn't leak when you are done it should be OK for the life of the car. I'd also be checking out the reason why they rusted through in the first place. Is the area holding water? I've completely lost the brakes on three vehicles I've driven over the years, I can remember like it was yesterday all three times! Two of them were old single brake systems, the other was a friends vehicle I was driving and evidently the back system had already gone out for some time and the front system let go. That's when the parking brake suddenly becomes the emergency brake, and believe me they don't do much good when you really need to stop.

Reply to
Moe

Hmmmm... To clarify, properly functioning rear brakes to add to the braking, whether the vehicle is front wheel or rear wheel drive, otherwise, manufacturers would not install them.

No offense to Moe, but should someone take brake repair advice from someone who has lost the brakes on two vehicles he is responsible for servicing, regardless of whether it is a single or dual system?

Reply to
Ray O

Jack replies:

Thanks for your insights.

I'm definitely going to investigate the condition of the high-pressure gas line.

I would like to replace my two rotted brake lines completely (one piece). Problem is, the steering assembly goes right across the bottom of the firewall, and it's a mystery to me how they've attached the plastic cover (over the lines) which curves from the front of the underbody up onto the bottom of the firewall.

Is there some way to remove this plastic cover? (Without removing the steering assembly!) Can the brake line be shoved up between the firewall and the steering, and then bent (wrestled more likely) into place by hand?

This line looks way thinner than what they have at the Partsource store. I think this line is about 3 mm ID or one-eighth inch ID. Is there a supplier in southern Ontario who sells this stuff by the foot?

Thanks again for the safety-conscious and helpful advice.

- Jack

Reply to
Ralph

Plastic covers are either screwed on or snapped in place.

Sorry, it's been a long time since I looked at the underside of your model car and I don't remember how the brake lines are routed.

Brake lines are generally sold in fixed lengths, like 5 or 6 feet.

Reply to
Ray O

Three vehicles! A 61 Chev pickup, a steel line was corroded through from the outside, a very small pinhole. An old Comet, a rear wheel cylinder blew out, went through a fence and into a pasture. A friend's Mazda pickup, an old one with drum brakes on all four wheels. The good old days. If a person hasn't learned trying to stop using only the hand brake they are missing a valuable driving (stopping?) skill.

Reply to
Moe

Very true!

Reply to
Ray O

Fred Flintstone used only the foot brake ...

Reply to
Philip

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