Author Topic: Brakes Questions  (Read 7488 times)

J. Huber

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Brakes Questions
« on: January 30, 2012, 20:49:25 »
So it has been about 7 years since I had my brakes done. In mileage terms, I think its only been about 10,000-12000 miles.

Next time around, I am thinking of doing them myself... but first:

Question 1: How do I check the present condition of the front pads (ie what do I measure and what's good/ not so good?)

Question 2: Even if pads & shoes are ok for now -- would it be wise to change the brake fluid and the flexible hoses anyway? I know I've heard 5 years on the hoses that can wear out from the inside.

Question 3: To be announced!

James
63 230SL

stickandrudderman

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Re: Brakes Questions
« Reply #1 on: January 30, 2012, 22:24:40 »
Brake fluid should be changed every two years regardless of mileage. It's hygroscopic so its boiling temperature is reduced over time. Boiled brakes can ruin your day.
I tend to fit stainless briaded hoses that will not need changing again for a very long time unless the customer insists on having originals.
Pad thickness is determined visually by comparing to new. The dealer philosophy is to change the pads if the technician thinks they won't make it to the next service before being worn too thin.
Too thin is subjective but I personally never let a pad get lower than around 4mm in thickness (of the friction material) and will quite happily change them with 5 or 6 mm remaining if they've been in there a long time. Always ensure that the pad wear is the same across the axle (4 pads). If you see one pad that's thicker than the others then you've probably got a stuck piston in the caliper. Conversely, if you've got one pad that's very thin then you've probably got a restricted brake hose. In this instance I would most likely change the hose, the fuid, the pads and the discs. Not only will braking efficiency be restored but your fuel efficiency will too.
If you've got any wear on the discs then you'll have a lip on the edge of the disc and this lip will cut into the pad so the pads will have to be changed sooner.
Discs that are very old should be changed regardless of measurable wear as they harden with use and time and braking efficiency is reduced.

J. Huber

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Re: Brakes Questions
« Reply #2 on: January 31, 2012, 05:09:29 »
Thanks Stick. I plan to buy the new hoses very soon -- then will be back here for some how-to info on changing them and the fluid. In the mean time I'll inspect pads. If I need new ones, is there a standard type/brand anyone recommends? P/N?

Related question: if I decide to replace my very yellowed brake fluid reservoir with a nice new white one, I will want to do that in tandem with the fluid change, correct? Is it difficult to replace? THX
James
63 230SL

pagoden

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Re: Brakes Questions
« Reply #3 on: February 08, 2012, 07:00:36 »
James, I took Jim Villers' advice from previous PUB presentations and replaced my pads with carbon/Kevlar pads about a year and a half ago, and am very happy I did.  Some phone calls and a little poking around on the 'Net led me to believe that Porterfield has the most reasonable product for our needs.  [There are some pretty crazy-sounding pads out there.]  Porterfield has been in the biz for ages and has a wide product range, including industrials and extreme-sounding racing pucks.  Their R4-S pad compound is for street and maybe a little light track use.  It is not at all ceramic, metallic or even semi-metallic.  As Jim promised, they seem very kind to rotors and are even much less schmutz-producing than the OEMs that preceded them on my car.  They cost more than 'regular' pads, but I'd do it again and again.  I'll let you compare the current prices; they're sure worth the extra bucks to me.  They are not only more 'civilized' in the ways mentioned above, but they just like to stop the car.  They are not the least bit grabby or radical, need no warm-up exercises to get to an elevated operating temp or anything exotic at all, won't snap your neck or lock up your wheels - - unless you want them to.  They're very civilized yet just plain like to stop the car; I love 'em.

During the search Google turned up a fellow in Illinois who markets accessories for high-end sporters.  He sells Porterfields at the same price that Porterfield does.  They are shipped direct from Porterfield with an extra kit of detailed installation instructions and hi-tech nostrums included at no cost only with orders through his business, MyRoadster.Net.  Jerry Jones has a toll-free # and several other modes of contact as shown on his website, www.myroadster.net.  He took a little time with me on the phone: the reason for the kit's inclusion was some earlier complaints of low-speed squealing with these and other, more race-oriented pads, something not at all unusual with disc brakes, especially the higher-performance types.  Mr. Jones likes things done right, and he apparently doesn't mess around.  Installation using the kit and its procedures is like painting; the hardest part is the surface prep. It's an ordinary brake job; the prep procedures are extensive but make sense and are pretty much what should really be done anyway in order to do it right and get best results.  We didn't get quite all the iis dotted and tees crossed on my car and still they are a great improvement; pick your own level of Pagoda preparation perfection.  Catalog info online at www.porterfield.com, more specs and installation prep preview on the MyRoadster site.  [Our cars take AP31 and AP45 pads.]

Denny
1968/69 280SL, just+100k mi, manual 4, 3.46, both tops, 717/904

Garry

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Re: Brakes Questions
« Reply #4 on: February 08, 2012, 08:03:02 »
Denny do you have the part number as there are lots of different R4-S pads that Porterfield have
Thanks
Garry
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Naj ✝︎

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Re: Brakes Questions
« Reply #5 on: February 08, 2012, 12:04:36 »
Hi, James,

Thanks Stick. I plan to buy the new hoses very soon -- then will be back here for some how-to info on changing them and the fluid. In the mean time I'll inspect pads. If I need new ones, is there a standard type/brand anyone recommends? P/N?

Related question: if I decide to replace my very yellowed brake fluid reservoir with a nice new white one, I will want to do that in tandem with the fluid change, correct? Is it difficult to replace? THX

You need to check what brand calipers you have. Early 230 SLs started out with Girling and they use different pads compared to later Bendix or ATE calipers. Also, the 230 brake discs (rotors) are a smaller diameter than later ones and not interchangeable.

You have to empty the brake fluid resevoir and use a spark plug wrench to undo the special bolt that secures the resevoir to the m/c. You can get a new kit with seals etc.

Naj
« Last Edit: February 08, 2012, 20:50:48 by Naj »
68 280SL

pagoden

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Re: Brakes Questions
« Reply #6 on: February 08, 2012, 19:37:18 »
Garry, your 280SL should take the part numbers I posted, but the 230SLs ares a different matter.  I'm sorry for not considering the earlier models; Naj is quite right, I'm sure.  See somewhere on Jones's website the notation that antiques and/or classics can often be fitted, consultation offered.  Contact him by the several methods also listed on the site.  Of course, I'm spoiled and just pick up the phone, which has worked well with Porterfield.  They are a solid, old-line outfit, and if their first-tier phone people can't cope, the next tier surely can.  [I think "Nancy" cut through the fog for me once; it's not that she's encyclopedic about the old-timers so much as a capable honcho.]  And, back to Jerry Jones: he obviously has an established line to Porterfield's experts.  The scales on which these two businesses operate appear to be very different, but they're both likely to get requests for the unusual, from competition to collectibles.
Jim Villers broke this ground a few years back.  I don't foresee big problems with correct fitment but if diffugalties do arise, he may have been there afore, at least with Porterfield.  I believe they'll make most anything, especially with the frame cores provided, but that our applications are not that exotic, possibly requiring a little conversation at most - - for standard part numbers that just may not be listed 'out front' these days, yes?   

Denny
1968/69 280SL, just+100k mi, manual 4, 3.46, both tops, 717/904

mdsalemi

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Re: Brakes Questions
« Reply #7 on: February 08, 2012, 20:24:21 »
Catalog info online at www.porterfield.com, more specs and installation prep preview on the MyRoadster site.  [Our cars take AP31 and AP45 pads.]

Sure about that link?  On my computer it brought up a web page for a real estate agent in Hinsdale, IL.... :-\
Michael Salemi
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IXLR8

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Re: Brakes Questions
« Reply #8 on: February 08, 2012, 23:09:55 »
Hi--

If you are redoing your brake hoses, the reservoir and master cylinder, why not go all the way and change your brake fluid to silicone?

It does not adsorb water as the conventional brake fluid does, it does not attack hoses and seals, and does not require changing every few years.

I replaced my factory brake fluid with silicone in my R107 about twenty years ago, and it is just maintenance free.

When I finally get ready to get my 230SL on the road, I'm going with the silicone.



the other Joe

Jordan

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Re: Brakes Questions
« Reply #9 on: February 09, 2012, 00:20:45 »
What brand of silicone fluid did you use?  Has anyone else ever used this?  Why is this not used more universally, is it expensive?  Thanks.
Marcus
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Benz Dr.

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Re: Brakes Questions
« Reply #10 on: February 09, 2012, 00:40:47 »
Slicone is more exspensive and I think it's DOT 5 but I could be wrong about that.

 I know it's not recomended for 190SL's and for good reason. The vacuum port is on the bottom of the brake booster on those cars any leak will go straight into the engine. Silicone doesn't smoke very much as it runs through an engine, unlike mineral type brake fluid which will produce white smoke, so it's hard to see if the booster is failing.

 On a 113 car this isn't an issue because the vacuum line is mounted much higher on the booster. One of the problems with silicone still involves moisture. Any water that gets into your brake system, while using silicone, will pool at any low spot in your brake lines. Over time that moisure can rust a hole through the line. With mineral fluids the water will stay in solution and can be flushed out. I recommend yearly fluid changes in high humidity environments such as the gulf coast or great lakes areas. Dryer areas such as Arizona are probably fine every other year.
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ja17

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Re: Brakes Questions
« Reply #11 on: February 09, 2012, 04:51:21 »
I have been using the new "sythetic" brake fluid made by Valvoline. It is less hydroscopic  than standard brake fluid. I believe it is dot 4. Also it does not damage paintwork like standard brake fluid. Anyone else have any experiences with it?
Joe Alexander
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pagoden

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Re: Brakes Questions
« Reply #12 on: February 09, 2012, 07:14:50 »
Garry, Michael & any others interested -

Correct url for Porterfield is  www.porterfield-brakes.com.  [Could some conflict with a real estate agent have driven them to add that?  They can be tenacious creatures.]  It may teach me to go back and check for changes.  Very sorry all.

Garry, I still don't expect you to run into any serious trouble with either of these companies, but if you do I'd be glad to make phone calls for you from here.

Denny
1968/69 280SL, just+100k mi, manual 4, 3.46, both tops, 717/904

stickandrudderman

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Re: Brakes Questions
« Reply #13 on: February 09, 2012, 16:49:41 »
Quote
It is less hydroscopic  than standard brake fluid

Actually, it's less hygroscopic.

Don't worry, I'm a trained professional and for the first 25 years of my career I was using "hydroscopic" too!

JamesL

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Re: Brakes Questions
« Reply #14 on: February 09, 2012, 18:00:10 »
Begging the question: Trained Professional in what??? ;D ;D ;D

Hope Switzerland is not too cold

Had a chat with Aidan McK today when I was collecting my 202: his wife's SLK320 was in and I gather he has something of a fleet you look after!
James L
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