Rear Brake Line Flaring Topic is solved

[abscate]

The drip isnt so important (catch the mess in a POISON LABELLED container) since you are going to push 250 mL of fresh brake fluid through your repair, anyhow.

[FireFox31]

A depressed brake pedal closes the valve, hence no drip, other than gravity at work.

Great tip, thanks! I'll try pressing the pedal down half way using a stick.

[FireFox31]

The flare on a brand new Volvo rear brake line part 3546365 has 90 degree angle base and a low, single angle head. The Volvo brake line fitting ("bolt") has a flat head to press against this flare base. As defined by the attached picture, it's a "DIN mushroom" flare.

cn90 used the attached image in his BMW forum post. See how the base (inside the fitting) of the bubble flare and double flare expand out on a diagonal? The mushroom flare base expands out at a right angle.There's lots of variation among information online, like Fedhill identifying only mushroom as "DIN/ISO bubble" and MFCP showing "DIN mushroom" having a double angled tip.

I mention all of this because of confusion when I bought my fittings. I went to a Federated / Fisher Auto Parts where they sell SURR brand fittings as shown on SURR catalog page 6. I asked for "bubble flare M10 x 1" and was handed a BR230 with a tip which appeared to angle inward like a double flare. I questioned it and was shown two other bubble M10 x 1; the long blue BR250 "for VW/Audi" (similar to AGS BLU8B which cn90 recommended) and the flat tipped brass BR255 "for Ford". Having the Volvo brake line in my hand, I compared and the BR255 "for Ford" was the best match in length, hex head width, material (brass, not black or blue), and flat tip.

Be sure that your fitting tip matches your flare base. Does Volvo use bubble or mushroom flare? Their tip angles differ, so this seems important, but I can't find any more definitive information than what I've posted here. I hope this info can help unravel what Volvo is doing so people get the right fittings and make the right flares.

Let me know if you need one or two new, sealed part 3546365 right rear brake line (bought for a 2000 V70 NA). It can be cut down and flared to fit the shorter left side. This was my plan before this thread taught me I could flare my existing lines.

[FireFox31]

Does anyone know where to get true brass brake line fittings like the Volvo originals? This SURR ones I bought are "brass" painted steel and I don't want it rusting in my new calipers. I've searched hard online and can't find our M10 x 1 x 3/16" bubble flare fitting in brass. Not even generic sites like McMaster-Carr.

[abscate]

Bumping this thread for Grunhilde

[scot850]

How about this company. Not sure if this is the 'right' ones but they are in stainless. However, they may have other options. It would appear that they fittings are UK type so maybe that is another option for a source? :

https://www.ebay.com/itm/224305637166?_ ... %3A2047675

Neil.

[abscate]

That same seller is selling made up bubble flare lines for $15 ! I can’t make them that cheaply!

[FireFox31]

tl;dr: Brass fittings are too soft and get destroyed, use stainless if available, use steel if you have to, and coat the fittings with Fluid Film to prevent rust.


I no longer think that brass fittings are the best option for these cars. It's great that they don't rust but their hex heads round off too easily because they're soft. I suspect they're difficult to remove because the caliper hole gets rusty around the top of the fitting, shrinking the opening a bit, gripping the fitting. When you remove the fitting, the smaller hole flattens the soft fitting threads on its way out. And because the hole is smaller, a new fitting with properly pointy threads won't fit in. This is exactly what happened on my rusted rear caliper. I had to reuse my ruined fitting because only its worn threads would fit back into the caliper (and its ruined hex head had to be machined to be usable again).

A tap might be required to rethread the caliper, opening the hole back up to the correct size. A die might help to rethread the fitting. I'm looking for an M10 x 1 tap and die set to test this out.

Instead of brass, I want to get whatever fittings Mercedes used in the early 2000s. They're probably stainless. The front brakes on my 2002 E320 use fittings (instead of a screw-in hose). A few days ago, I was able to remove one of these fittings for the first time in its life with minimal effort. The head didn't strip, the threads were perfect, and neither the caliper nor fitting had any rust on them. I plan to ask the Mercedes dealership and forums about those fittings.

To protect the fitting and caliper hole from rust, I recommend applying Fluid Film after installation. It's a wax-based coating which is supposed to prevent rust by not allowing moisture in. I recently replaced a pair of fittings with SURR BR255 while installing new rear calipers. I'm really hoping this light coat of Fluid Film will make the fittings possible to remove in a few years when the calipers fail.

Ultimately, I blame Volvo, Cardone, and other caliper rebuilders for doing a terrible job at coating their rebuilt calipers. My caliper rebuild and paint thread documents my terrible experiences with these products. The calipers should have proper rust protection like on my Mercedes, which is 20 years old and spent 15 years with me in the same conditions as my Volvo, but the calipers look excellent. We get calipers which rust out in a week, requiring the fittings to be cut off and flared in order to remove the caliper.

Actually it's more than just the calipers. Mercedes used better rust proofing on all of its suspension parts. The above picture shows no significant rust on the 20 year old spring, strut, steering knuckle, dust shield, sway bar, control arm, etc. I drive that car through more snow and salt than my V70 because it has AWD. However, the body of the Mercedes rusted badly. The Volvo body shows no rust but all of its replaceable components have rusted. This shows that both halves could be made to not rust but neither manufacturer chose to do so.

[abscate]

$10 Amazon

https://www.amazon.com/Atoplee-Metric-T ... NrPXRydWU=