| Author |
Message |
    
Norm
| | Posted on Monday, November 04, 2002 - 03:37 am: | 
|
This is on a '95 Disco with a little over 60K miles -- suddenly got spongy after changing out the fluids to Ate Dot 4+ blue. The funny thing is, the brakes and clutch worked great before with absolutely filthy fluid in them. Have bled both systems (the clutch actually got worse -- with only about an inch or two of clutch at the bottom of the pedal). No signs of leaks anywhere. I unplugged the ABS long ago.
Is this a sign that the master (or slave) cylinders are going bad or could it be in the calipers or all the above?
What is my next course of action?
Thanks,
Norm |
Bill Bettridge (Billb)
| | Posted on Monday, November 04, 2002 - 08:53 am: |
|
Try going back to standard fluid - like LMA, etc and see what happens.......I though that blue race fluid was not really for everyday use anyway?
Bill |
Pugsly (Pugsly)
| | Posted on Monday, November 04, 2002 - 08:58 am: |
|
Since it happened after you changed fluids I would re-bleed the system completely. Easiest thing to check and most likely air in the system is root cause. I'm assuming that the fluid was from brand new bottles that you broke the seal on to open and you didn't leave the system open to the air for very long?
It's unlikely that both clutch and brakes would fail independently and a the same time. What's in common between them? Only the new fluid and bleeding job you did. |
Ed Petrush (Exp3)
| | Posted on Monday, November 04, 2002 - 09:28 am: |
|
I would agree with Pugsly... I would rebleed the system.. it sounds like you did not bleed either system properly. |
muskyman
| | Posted on Monday, November 04, 2002 - 09:33 am: |
|
good luck you may have really messed up the system
dot4 is synthetic and some seals(such as master cylinder) will never seal again after they have been exposed to dot4.
i'd flush both systems completly before trying to drive it for sure |
perroneford
| | Posted on Monday, November 04, 2002 - 09:37 am: |
|
Musky,
Dot 5 is synthetic. Dot 4 is normal brake fluid.
-P |
Paul T. Schram (Paulschram)
| | Posted on Monday, November 04, 2002 - 11:32 am: |
|
Thanx P, I thought for sure the LMA I had bought said that it was DOT-4.
Paul |
Dave_Lucas (Dave_Lucas)
| | Posted on Monday, November 04, 2002 - 02:59 pm: |
|
Perrone,
I have a bottle of DOT 4 synthetic at home.
Actually, I could only find dot 4 in synthetic so that is what I am using in my DII right now |
perroneford
| | Posted on Monday, November 04, 2002 - 03:03 pm: |
|
DOT4 synthetic is fully compatible with DOT4 non-synthetic. Dot 5 is the stuff that causes problems as it is NOT compatible with DOT4 and it is not for use in ABS equipped vehicles. This is the stuff that has to be flushed out if you use it. |
Dave_Lucas (Dave_Lucas)
| | Posted on Monday, November 04, 2002 - 03:07 pm: |
|
Cool,
Thanks for clarifying that for me. |
Greg H
| | Posted on Monday, November 04, 2002 - 04:06 pm: |
|
The DOT ratings really have nothing to do with being synthetic, silicone, or glycol-based but really refer to the minimum wet or dry boiling temps of the fluid. Thus DOT 5 could be made from anything as long as it has as certain minimum boiling temp that is obviously higher that DOT 4, etc.
The ATE blue fluid that you refer to is an excellent quality glycol-based brake fluid with very high wet boiling temps. I have used this in my Porsche 914-6 with good results. Unfortunately it is VERY HYGROSCOPIC (meaning it has a high propensity for attracting moisture/water in the system). I would only use it in a high performance vehicle that I change brake fluids in very frequently (i.e racing).
Dot 5 can be made from anything but I only know of it being made from silicone currently. I believe there are only 2 mfgers currently making DOT 5 even though many brands selling it. If you buy some that is purple-colored it is made by General Electric no matter what the label says. Silicone is NON-Hygroscopic (does NOT attract water) and is standard in most govt. vehicles and Hummer H1's.
I have also heard of DOT 5.1 brake fluids that have even higher minimum wet boiling temps but have never used them. I believe Lucas and ATE both mfgr them and they are pricey. I don't know what they are made of.
By regulation ALL DOT rated brake fluids must be compatible with each other no matter what they're made of. However, I have heard horror stories of people having corrosion in their systems from silicone isolating moisture in their systems even after reflushing with glycol-based fluid. A total teardown and cleaning was required.
I personally only use Castrol LMA (low moisture absorbtion) DOT 4 in my RRC and have had good luck with it. It's available just about everywhere. There are other DOT 4 fluids on the market (Valvoline, etc.) that say "synthetic" on them but I don't know what that means in brake fluid or what advantage it would give. (standardized molecular structure?)
just my (lengthy) 2cents |
muskyman
| | Posted on Monday, November 04, 2002 - 04:26 pm: |
|
"Musky,
Dot 5 is synthetic. Dot 4 is normal brake fluid."
read the lable!...he said dot 4+ I have never seen a dot4+ that was not a synthetic
"By regulation ALL DOT rated brake fluids must be compatible with each other no matter what they're made of. However, I have heard horror stories of people having corrosion in their systems from silicone isolating moisture in their systems even after reflushing with glycol-based fluid. A total teardown and cleaning was required."
this is not true from what I have seen many dot4 bottles clearly state not to be used in a system with other then dot4 fluid. I ended up flushing like 6 different BMW's after a road course event because someone shared dot4+ redline with a number of guys during the tech inspection .
IMHO a good complete flush will serve just about every brake system there is in nothing but good ways so dont delay...flush today |
Greg H
| | Posted on Monday, November 04, 2002 - 05:06 pm: |
|
hehe-I like the "don't delay, flush today" but there should music playing too!
You are right-many bottles DO say not to mix DOT rating brake fluids. This is because your brake fluid is only as good as the lowest rated fluid installed. Thus if you had filled and properly bled your system with expensive DOT 5.1 and then topped off your reservoir with el cheapo DOT 3, your entire system would now only have the minimum wet boiling temp of the lowest rating DOT 3.
Most (at least mine) LR's say in your workshop manual "Brake fluid must have a minimum boiling point of 260C (500F) and comply with FMVSS/116/DOT 4" and right on the reservior "Use only DOT 4 brake fluid". The temp referred to is NOT wet boiling temp.
Other auto mfgers (i.e VW) specifically say NOT to use DOT 5 (silicone) fluids as "corrosion may result". It's my understanding that this is not because incompatibility issues but rather because the corp. attorneys don't want people assuming they never have to change their brake fluid. (Some silicone mfger advertised longer or NO changes needed cause DOT 5 is non-hygroscopic).
Mixing types of brake fluids is NOT a good idea, however, according to govt regs they ARE compatible meaning they won't catastropically react to each other.
I personally wouldn't even mix brands of DOT 4 just as I wouldn't mix brands of the same viscosity oil in my engine. |
Greg H
| | Posted on Monday, November 04, 2002 - 05:29 pm: |
|
hehe-I like the "don't delay, flush today" but there should music playing too!
You are right-many bottles DO say not to mix DOT rating brake fluids. This is because your brake fluid is only as good as the lowest rated fluid installed. Thus if you had filled and properly bled your system with expensive DOT 5.1 and then topped off your reservoir with el cheapo DOT 3, your entire system would now only have the minimum wet boiling temp of the lowest rating DOT 3.
Most (at least mine) LR's say in your workshop manual "Brake fluid must have a minimum boiling point of 260C (500F) and comply with FMVSS/116/DOT 4" and right on the reservior "Use only DOT 4 brake fluid". The temp referred to is NOT wet boiling temp.
Other auto mfgers (i.e VW) specifically say NOT to use DOT 5 (silicone) fluids as "corrosion may result". It's my understanding that this is not because incompatibility issues but rather because the corp. attorneys don't want people assuming they never have to change their brake fluid. (Some silicone mfger advertised longer or NO changes needed cause DOT 5 is non-hygroscopic).
Mixing types of brake fluids is NOT a good idea, however, according to govt regs they ARE compatible meaning they won't catastropically react to each other.
I personally wouldn't even mix brands of DOT 4 just as I wouldn't mix brands of the same viscosity oil in my engine. |
Greg H
| | Posted on Monday, November 04, 2002 - 05:31 pm: |
|
oops-SORRY for double posting! |
perroneford
| | Posted on Monday, November 04, 2002 - 06:19 pm: |
|
Musky,
ATE is just good DOT4. I have some on the shelf as we speak. I use it in the BMW and have for years. It is not synthetic and no flush is required to switch back and forth with other DOT4 like LMA.
My container of LMA indicates that it exceeds DOT4 specs.
Sorry, Musky. Nothing personal, I just think you're wrong on this one and others here seem to agree with me.
-P |
muskyman
| | Posted on Monday, November 04, 2002 - 08:25 pm: |
|
perrone...? personal?...dont worry about that its about getting the right word across and it is.
yes in my first post I was thinking dot5 and typing dot4 ...brain cramp...just to much worthless info up there clouded by to many things in the front of my head.
dot5 is the one that has caused problems with seals in master cylinders leaking.
but it was synthetic dot4 redline that caused all the problems in the BMW's at the track i mentioned and they all had spongy pedals after mixing it into conventional dot4 brake fluid.
thats what made my mind fart I guess |
perroneford
| | Posted on Monday, November 04, 2002 - 09:56 pm: |
|
Ok cool. I know some people get into pissing contests and I was just trying to avoid that here. You've always seem cool and logical so no sweat.
I've never heard about BMW's having DOT4 issues. I run ATE DOT4 in mine without issue. I've never tried the redline though.
-P |
Norm
| | Posted on Monday, November 04, 2002 - 11:23 pm: |
|
Thanks to all for the input!!
My mechanic (120 miles away) put the Ate Blue racing fluid in the brakes -- he said it was Dot 4-plus, whatever that means. I can't seem to find anything here by Ate but the Dot 4 original formula, which is yellow. He suggested I bleed the brakes again a time or two before doing anything drastic. I assume there'll be no problems mixing the blue with the original formula.
I fixed the clutch myself by bleeding again (following the Haynes manual procedure this time) and filling with the Ate original formula Dot 4.
---Norm |
perroneford
| | Posted on Tuesday, November 05, 2002 - 12:06 am: |
|
ATE comes in blue and gold. In my BMW I alternate as it is immediately apparent when all the old fluid has been pushed out, leaving only the new color in the lines.
DOT4 Plus just means it exceeds the standrds for DOT4 fluid. I'd also suggest you getting a pressure bleeder if you can spare the cash. I bought a Motive Bleeder a couple of years ago and it's been terrific. I didn't know any other Rover guys using it when I bought mine, but now everyone seems to have them. They are cheap at around $50, and they work incredibly well.
-P |
Ron
| | Posted on Tuesday, November 05, 2002 - 01:34 am: |
|
What is so hard about using GT LMA?
I mean really, use stock filters and plugs and GT LMA and non synthetic trans fluid you won't have issues. No one seems to learn. 
Let this be a lesson to the rest of you.
Norm, rebleed and it "should" be fine. Bench bleed the masters if a normal bleed fails.
Ron |
Norm
| | Posted on Wednesday, November 06, 2002 - 02:10 am: |
|
Ron,
Will bleed at the calipers again soon.
What's a bench bleed, though? Does that necessitate removal of the mastercylinder?
In the mean time, I'll keep a firm grip on the emergency brake!!!
---Norm |
Closed: New threads not accepted on this page