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DOT 5 in 308 Brake System?

Discussion in 'Technical Q&A' started by rickjaffe, Mar 24, 2005.

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  1. rickjaffe

    rickjaffe Formula Junior

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    #1 rickjaffe, Mar 24, 2005
    I have this break issue, where the wheels don't lock up. I've got a good general mechanic who does alot of brake work. My break fluid which hasn't been changed in six months at least is brownish, which he says is from rust in the system. He's recommending I go with DOT 5, rather than the DOT 4 which it presently has because he says the DOT 5 silicone won't absorb moisture (I live in houston and there's alot of moisture here). Any problem using DOT 5 in a 308 GT4; If it matters, it's a southern car; no hard winters, no driving in mountain ranges.
     
  2. greg328

    greg328 F1 Rookie

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    #2 greg328, Mar 24, 2005
    not to be rude, people, but it's: "brake", not "break". I'm sorry, mis-spellings just really bug me.....!

    Greg
     
  3. pma1010

    pma1010 F1 Rookie

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    #3 pma1010, Mar 24, 2005
    From what I recall, you don't mix the two (DOT 3/4 and 5) types. I believe DOT5 is fine for road use. Bad news at the track, but OK on the road.

    Anyone know if it is compatible with the seals used in the 308 calipers?
    Philip
     
  4. Iain

    Iain F1 Rookie

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    #4 Iain, Mar 24, 2005
    He's right in that DOT 5 doesn't absorb moisture - which means if there is any moisture in the lines it just sits as liquid water.

    DOT 3/4 doesn't mix with DOT 5 which means that really you should flush the entire system with some kind of solvent in order to switch to DOT 5. In short, I wouldn't do it. DOT 5 is normally recommended for cars that rarely move. If you have rust in the system then the only thing to do is to clean it out. Maybe flushing the system two or three times over a 3 month period will fix it - if not the right answer is probably to strip it down & clean it out properly & rebuild calipers/cylinders & replace pipes etc. And/Or you could look at the 355 brake upgrade.

    rgds

    Iain
     
  5. rickjaffe

    rickjaffe Formula Junior

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    #5 rickjaffe, Mar 24, 2005
    what is a 355 upgrade? just putting the calipers and other hardware from a 355 on the 308?
    I guess the first thing I want to do is try to get the brakes to lock up; first step is to see if there's air in the system; since the fluid is brownish and I just bought the car, I'm in the process of changing all the fluids anyway, so since I've got to have it bled, it seems to make sense to drain the entire system with fresh brake fluid, to do it right and see if that solves the locking up problem. Apart from no locking up the brakes are adequate, but I'm comparing them to hydro assist racing type brakes (plus new brake braided lines and calipers which I had installed on my mid year corvette); and the brakes on that car are terriffic. So maybe it's not fair to compare a completely new racing type system to an original 30 year old system which probably has air in it.

    I suppose there are all kind of options to consider to upgrade; cross drilled this or that. I know I can't put a hydro assist system in because that works off the power steering fluid, which the 308 doesn't have.

    so getting back to the basic question; if I have all the fluid removed, and then I guess run solvent through the system and then put in DOT 5, is that a good thing, or better than staying with DOT 4. there is zero chance of me going on a track; never have been on one, and I don't want to put the car and especially the brake system through the wear and tear of track (some guy I know tracks a corvette and tells me he can run through $1700 of brake and tire equipment in a weekend at the track. I'm just not that kind of guy).
    so will the braking be better with DOT 5? I'm going to use the car as a semi daily driver, mostly short trips. Or maybe it just doesn't matter for my applicaiton. that 's the question. thanks ian for you informative answer.
     
  6. rickjaffe

    rickjaffe Formula Junior

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    #6 rickjaffe, Mar 24, 2005

    Originally Posted by greg328
    Who/what is QV London and how do I contact him/them?

    Greg




    to grig318; the webb addresss is http://www.hamletcg.co.uk/qv/email.htm, P.S. (gettaliffe)
     
  7. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    #7 Dr Tommy Cosgrove, Mar 24, 2005
    I may be mistaken but I do not believe you can simply bleed the system out and then replace it with the silicone fliud. I think NO traces of the regular fluid, whatsoever, should mix with it. This means you really have to start from scratch. The calipers will need to be stripped and rebuilt - which they need anyway so there is no real-world advantage to upgrade your fluid after that. The problem will then be fixed. Normal brake fluid loves water. Your system got rusty because someone in the past didn't change it as they should have. It soaked up moisture and as a result things got rusty in there. My Alfa had a rear caliper that was so badly damaged by this that it couldn't be rebuilt. The piston was frozen solid (this was just after I bought it - it doesn't get treated that way anymore).
    For me the silicone is too much trouble just to save you avoidable trouble later, if that makes sense. Rebuild your calipers and from here on simply change the fluid every 6 months to a year and I bet you will never encounter this problem again. In fact I am sure you won't.
     
  8. rickjaffe

    rickjaffe Formula Junior

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    #8 rickjaffe, Mar 24, 2005

    thanks, that makes the decision easy. I'm sticking with DOT 4. I'm paying retail to do all this so I want to eliminate unnecessary labor. So it seems first we'll inspect the calipers, put in fresh brake fluid, get the air out of the system, and see where we are vis a vis the non-locking brakes. I'm looking into the 355 upgrade, but if I can just get them to lock up, that would be a big improvement. thanks
     
  9. pma1010

    pma1010 F1 Rookie

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    #9 pma1010, Mar 24, 2005
    Is a parts, service and race shop in the UK run by Mike Lester and Phil Warburton. Based in SW London. Their cars have run PFMC and classic series etc. Anyway, you can find them on the web or look for them with "search" and you'll find them.

    355 upgrade is a kit they made. Search on it and you'll see some pics of my set up which is made using a variant of their kit.

    If you just use the car on the street just get everything cleaned up and enjoy it.
    Philip
     
  10. ferrarifixer

    ferrarifixer F1 Veteran
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    #10 ferrarifixer, Mar 25, 2005
    You can mix all the fluids you like, however a Mineral based one such as Citroen must not be used as it will have a chemical reaction making the rubbers swell and fail.

    Otherwise, any mixing between any DOT # even silicone will NOT damage anything, it will simply be only as good as least performing fluid in there.

    A 308 will lock it's brakes easily if everything is healthy.

    I'd suggest your brake booster/servo is faulty, or you have glazed pads/discs, or even really old pads that have gone too hard.

    The booster itself can be bad through a failed diaphragm oir other reason, or just bad vacuum lines / one way valve or something.

    Maybe you have an engine problem causing poor vacuum too. Many Ferrari have extra vacuum pumps to overcome this, and 308's missed out, but they can have problems making vacuum if tuned badly.
     
  11. rickjaffe

    rickjaffe Formula Junior

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    #11 rickjaffe, Mar 25, 2005

    the car hadn't been run much before I got it (two weeks ago); the brake pads (porsche, not ferrari, I was told) are fairly new. we'll check them also; if they're ok and there's no air in the system and the fluid is changed, then I guess diagnositically, it's on to the booster (master feels allright in that there is no e pedal travel to the bottom on slowly depressing the pedal). for my own edification, how do test the booster?

    also had a multi year brake problem in my 66 lincoln; it had two valves; metering and proportion. the front brakes also couldn't lock up; it would be fixed and the problem would reoccur after 10 miles. turned out the valve (proportion, I think) had a small leak which was sucking in air; we removed and bypassed the valve and solved the problem (I had already replaced that valve once and didn't want to do it again). so I'm wondering if I might have air in the system.

    the guy I bought the car from was knowledge, and hands on, but had little ferrari experience. he didn't know for example the air removal techniquie for the coolant, and the fluid is brown which means it hadn't been changed on schedule, so I'm hoping it's something simple like air in the lines. we'll see, thanks for the advice.
     
  12. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #12 Steve Magnusson, Mar 25, 2005
    One thing you might try is to remove the large vacuum line at the booster to test for presence-no presence of vacuum with the engine running.

    1. If vacuum is present, block the line with something to keep the engine happy (leaving the nipple on the brake booster open to the atmosphere) and (carefully) retest the braking feel -- if the feel is unchanged, you could be fairly sure it's something bad internal to the brake booster itself. If the feel is further changed (i.e., even weaker), then you'd be justified to start digging deeper into the other mechanics (You seem too anxious to jump into the deep end ;)).

    2. If no vacuum is present, it a case of checking the lines and the one-way vacuum check valve per the previous posts.
     
  13. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    #13 Dr Tommy Cosgrove, Mar 25, 2005
    Thankfully he needs no "Ferrari" experience to deal with the brake system on your car. There is nothing special or unique to it at all.
     
  14. pistole

    pistole Formula Junior

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    #14 pistole, Mar 25, 2005
    is being able to lock your brakes some kind of accepted brake test
    procedure now ?
     
  15. Iain

    Iain F1 Rookie

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    #15 Iain, Mar 25, 2005
    Not particularly - but I've never driven a car with a healthy system that couldn't do it (unless it had ABS!)

    I.
     
  16. rickjaffe

    rickjaffe Formula Junior

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    #16 rickjaffe, Mar 25, 2005
    update:
    took the car to my mechanic; we pulled the wheels, rotors and pads were ok (front were almost knew as the seller said); we bled out all of the old brown brake fluid. There was some air in the front brakes. as a result of the work,the car seems to stop with more authority; but they still don't lock and there is no skid. My guy didn't think it's the booster because he opines that even with a bad booster, ie power assist, they would still lock up if you press hard enough, so it shouldn't be the booster. Is there something incorrect about this logic?

    he also thinks the master seems fine. he said not to worry about it, and when the time comes to replace the pads think about it then. That's the same opinion as the ferrari mechanic I had take care of my shift selector problem gave me. so I guess I'll let it go. thanks to all for your advice. rick jaffe
     
  17. infraredline

    infraredline Formula 3

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    #17 infraredline, Mar 25, 2005
    If you are standing on your brakes and no wheels lock, you've got a problem. What happens when you press down? Does the car slow at all when you gently tip into the pedal? Does the pedal go to the floor? My concern would be if your brakes feel weak in normal day-to-day driving, what happens when they get a little heat in them on a spirited downhill run?
     
  18. rickjaffe

    rickjaffe Formula Junior

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    #18 rickjaffe, Mar 25, 2005
    no, the pedal doesn't feel weak or too hard; the car stopped ok in daily driving before; now after bleeding out the air; it stops better, and faster; If I just lightly depress the pedal the brakes start to engage; pressing harder, more brake action, more and faster deceleration. I can't say they feel weak (I've had weak brakes on another car); It's almost like I've got ABS; they stop and now stop pretty good, but I'm expecting with a non-abs system to be able to lock up the fronts and skid (which isn't necessarily a good thing to do, but presumably a non-abs car should do); now when I jam the brakes, the car slows quicky and in a straight line, but no wheel lock. that's about it.
     
  19. Iain

    Iain F1 Rookie

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    #19 Iain, Mar 25, 2005
    You would expect some improvement just from getting rid of the air & the new fluid. Old fluid tends to compress a bit so you should expect the pedal to be a bit firmer.

    Have you checked the flexible hoses? If one of those is weak & bulging slightly then that might account for the problem. Bottom line is you are simply not getting enough pressure onto the pads so something is either leaking or "giving" in the system.

    You could check the hoses by getting the car up on a ramp , start the engine & have one person press on the pedal while the other checked each of the hoses feeling for bulges as you press on the brakes. Its the only way I can think of that you could check them "under load".

    If it were me, I'd keep looking because if something is starting to give way, sods law says it will fail completely when you least need it to.

    rgds

    I.
     
  20. enjoythemusic

    enjoythemusic F1 World Champ

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    #20 enjoythemusic, Mar 25, 2005
    Hmm... have you tried (do you have) stainless steel (Goodridge) brake lines? Also, i had good results with EBC Green Stuff brake pads on the stock 308.
     
  21. pad

    pad Formula 3

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    #21 pad, Mar 25, 2005
    As stated before, take a good look at the rubber brake hoses. One way to check is to see how much fluid and with what pressure the fluid comes out at each brake while bleeding the system. This can be done simply by having someone apply hard pressure on the brakes while you open up each wheel's bleed valve. (You can not do this test with an automatic brake bleeder systems as used in most repair shops). By the way, if you see any brown fluid, you still have rust in the system. You may find that part of your problem is that you have a frozen brake piston(s). Just went thought all of this with a friend's 365 Boxer. We ended up replacing all the rubber brake hoses, and rebuilding the rear brakes that were partially frozen. That's the problem with letting these cars set around without using them. Good luck.
     
  22. rickjaffe

    rickjaffe Formula Junior

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    #22 rickjaffe, Mar 25, 2005
    the braided brake lines seems like a good idea; had succees with them on my vette; we bled out all of the brown stuff. no frozen piston that we could see; brakes work ok; just not great; I like the braid line idea; any leads on where to get them?
     
  23. enjoythemusic

    enjoythemusic F1 World Champ

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    #23 enjoythemusic, Mar 25, 2005

    The previous owner got them from http://www.TireRack.com and doing a web search it seems http://www.brakeworld.com also sells them. Am sure there are MANY other sources.

    FYI: if you get the Brembo or the Gyro brakes they include Goodridge brake lines.

    FYI: If you are using stock brake pads, seriously, change them to EBC or something with more grip. This WILL make the brakes more grippy BUT MAKE SURE THEY HAVE A GOOD WIDE TEMP RANGE. In other words, avoid 'race only' IF they MUST be really hot to properly operate. You really should have brake pads that also grip well when cold for normal/spirited street use.

    As i said before, had EBC on the 308 here and they were quite good and yes, i could lock them up if desired.

    i got bored, wanted to lower unsprung weight and enhance performance... Changing the fronts to the Brembo package and changing the stock rears with more agressive DS2500 pads DID make the 308 braking stronger BUT now the fronts to tend to lock up a bit easier them before and the rears seem a touch weak. Odds are i just need to do some brake pad changes to rebalance things.

    Again, search the archives. Oh heck, here are a few links...

    http://www.ferrarichat.com/forum/showthread.php?t=39712&highlight=brembo+308

    http://www.ferrarichat.com/forum/showthread.php?t=42270&highlight=brembo+308

    http://www.ferrarichat.com/forum/showthread.php?t=34874&highlight=brembo+308

    AND THE 308 BRAKE CHANGE IN DETAILS
    http://www.ferrarichat.com/forum/showthread.php?t=35287&highlight=brembo+308


    Hope this helps.
     
  24. rickjaffe

    rickjaffe Formula Junior

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    #24 rickjaffe, Mar 25, 2005

    I've been to both sites; they don't seem to have a kit for the 308. I assume the fittings are different on different cars, aren't they? so I need a 308 specific good... kit I think. that I haven't been able to find.

    don't think I'll go the brembo route, for one simple reason: cost, it's into double digit percent of my car's value. my new golden rule: "don't spend 40k into a 20k car." hundred buck brake line, ok $2500; new front brakes, no way. thanks, rick
     
  25. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
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    #25 Dr Tommy Cosgrove, Mar 25, 2005
    You will be able to lock them up with the Brembo kit if you want to. I have it on my 308.
     
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