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Conference terri::cars_uk

Title:Cars in the UK
Notice:Please read new conference charter 1.70
Moderator:COMICS::SHELLEYELD
Created:Sun Mar 06 1994
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2584
Total number of notes:63384

2153.0. "Aeroquip hoses for brakes on BMW 325i" by CLADA::JSMYTH () Tue Sep 21 1993 19:04

I have a BMW 325i (1986 model)

I have always noticed that the brake pedal is very spongy and that there is
quite a lot of travel before the brakes 'bite'. I have not complaints about
the effectiveness of the brakes, they stop the car fine. Its just that they don't
feel very powerful.

Bleeding the brakes doesn't improve the pedal hardness. The car has ABS braking.

I believe that one of the reasons for 'spongy brakes' can be that the brake hoses
expand under pressure resulting in a loss of pressure. I remember reading 
somewhere that braided steel covered hoses help by reducing the effect of the 
brake hoses expanding.

Does anybody have a telephone number or address for a company called 
AEROQUIP who I believe supply these hoses or indeed recommendations for any
other companies supplying a similar product.

Or has anybody experienced this problem in a BMW or other car and how did they
fix it.

Thanks.
JOhn
T.RTitleUserPersonal
Name
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2153.1I'll look it upFUTURS::LONGWY::LEWISTue Sep 21 1993 21:4810
    There is a company based at Castle Coombe racetrack that specialise in
    mail order for these hoses. I will try to remember their number for
    you. 
    I recently had a problem with a 13 year old bike which I could get no
    improvement on even after stripping down the calipers, fitting new
    seal, replacing the fluid, the pads, bleeding the brakes, I was still
    able to pull the level back to the handlebar. Fitting these hoses cured
    the problem immediately.
    
    Rob
2153.2FUTURS::SAXBYIs it friday yet?Wed Sep 22 1993 12:5410
    
    Re .0
    
    I don't know where you are based, but many better motor factors stock
    braided hoses. Try the local yellow pages.
    
    I had a set made up for the Marcos and, yes, they did improve the brake
    pedal feel a great deal.
    
    Mark
2153.3Won't do any harm...MOEUR1::KENNEDYGoing places ....Wed Sep 22 1993 13:375
    
    I agree about the new hoses, however, I also think it depends on what
    you are used to. If you refer to note 60 in this conference, somewhere
    I express my doubts about the brakes on an M3. This was not due to age,
    but was just the nature of the beast ....
2153.4correct me if I am wrong here...AYOU35::WARRENWed Sep 22 1993 17:0911
do these braided hoses take the place of the rubber hoses that lead from the 
servo (or master cylinder - I cant remember which) and join to the metal pipe 
leading to the calipers ???

Warren (whose Nova brakes are crud and needs them fixed)


Ps   Are mintex brake pads good ???
     How long would a set last *on average*
     Does anyone have an alternative ??

2153.5do it!UTROP1::BOSMAN_PWed Sep 22 1993 18:3824
    The "race" brake lines are teflon with a steel braided mantle.
    The teflon hardly deforms and so the lines almost do not expand. This
    results in a definite pressure point in the pedal/lever.
    Yes, they simply replace the rubber lines and you can have them custom
    made at almost any brake-specialists shop. It's fairly cheap, for my
    bike the front set-up cost me 70 PS.
    
    I value this mod so highly that all bikes I had were fitted with this.
    In cars the whole driving is far more remote so I don't think it's
    worthwhile. On very sporty cars however it would definitely make a
    difference.
    An adde advantage is that the lines are custom made and therefore
    usually do awy with several connections. On my present bike the system
    went from 11 down to 4 joints. Yes, this is arguably safer too.
    Another one is the weight involved. The braided line set-up is
    consideably lighter than the standard fitting. On cars this doesn't
    really add up but on light-weight competion bikes it sure does.
    
    So all in all: 
    For bike it's a go.
    For commuter cars it's no but for out and out sports cars it's go
    again.
    
    Peter
2153.6Potential rat hole but...AYOU35::WARRENWed Sep 22 1993 19:165
It's a Nova SR.  (those will argue it's sportyness)

Despite an uprated servo and calipers, the brakes are crap.

Might look into the hoses though  (no joke intended)
2153.7rally cars tooOASS::BURDEN_DThis is a Studebaker YearWed Sep 22 1993 19:536
We used these on the rally car for two reasons.  The first is for improved
brake feel as stated before.  The other was for added protection for the brake
lines against rocks and gravel being thrown at them all the time.  The metal
braid will withstand more abuse than the rubber coated lines.

Dave
2153.8Harder yes, but tougher???UTROP1::BOSMAN_PThu Sep 23 1993 11:5015
    Dave,
    
    Althouhg I, as mentioned before, always fit these line I am not so
    convinced they can handle more abused as I used to be.
    On my off-road ventures I found thet the flexibility of rubber makes it
    VERY tough wearing whereas steel shears/breaks with fatique or just
    stress. It is also quite impossible to permanently deform the rubber
    ones over a boulder but the teflon/steel ones will nick and stay bent.
    Since the new lines can be custom made they can be run tighter and
    better. Add some thin wall rubber tubing and tie-wraps at the most
    vulnerable spots and it's indeed bullet proof.
    
    Have succes with the comp. car btw.
    
    Peter
2153.9telm me more...AYOU35::WARRENThu Sep 23 1993 14:008
re .7


What kinda car you got dave ?
Where do you rally ???


Warren (very_interested)
2153.10Pulling my .....CHEFS::MARCHRThu Sep 23 1993 15:214
    I had a 325 with ABS, about the same year I think and I complained that
    the brakes were spongy compared to my previous 320. They said it was
    due to the ABS system plumbing. In other words not fixable?
    
2153.11NR750::WATSONRGod wants GiraffesThu Sep 23 1993 16:5418
2153.12OASS::BURDEN_DThis is a Studebaker YearThu Sep 23 1993 19:3914
Re: Have succes with the comp. car btw.

and: What kinda car you got dave ?
     Where do you rally ???

I used to have an '83 VW Rabbit GTI (Golf Mk I) that I rallied in US and
Canadian events from 1987 to 1991.  Had lots of fun, but I sold the car last
year to play with my new toys.

Besides 'a few' Isettas (just to keep this topic somewhat related to BMWs) I
have a 1924 Studebaker.  The Stude doesn't have to worry about rubber brake
lines, it has mechanical brakes (steel cables) and only on the rear wheels....

Dave
2153.13Bleeding brakes..VIVIAN::G_COOMBERI'd rather be surfingThu Sep 23 1993 20:0920
    rep a couple back.
    
    I have had all sorts of problems getting the brakes on my BMW K100LT to
    feel right. That too has ABS!!!! I Don't think the problem is the
    hoses. I base that remark on the fact the my other beemer does not have
    a problem getting the brakes right, and they both have pretty much the
    same hoses at the front. I did ask Goodridge at a show about braided
    hoses, Unfortunatly the guy was waffling, knew his pipes but nothing 
    about bikes. Poor guy got really confused when I told him 90% of the
    brake pipe was copper and it had abs too. 
    
    I suspect that there is something in the ABS pump story. I have changed
    the fluid more times than I can remember and bled the brakes more times
    than I can remember. According to the Clymer and the Haynes manual I 
    have for it , they go to some length to tell you that abs systems need
    to be power bled because of the amount of fluid and pipe involved.  I
    can only assume they mean using a pressure system to back bleed the
    system rather than age old method with a jar and a length of pipe.   
    
    Garry
2153.14Breaky, breaky...UTROP1::BOSMAN_PFri Sep 24 1993 13:0427
2153.15More pipe workVIVIAN::G_COOMBERI'd rather be surfingFri Sep 24 1993 13:2115
    
    Thanks for that,
    
    	To some extent I took what the dealer I bought the K from as Sh***,
    mainly because of their attitude, (they since lost the franchise). The 
    Haynes manual frequently says take it to BMW for jobs I feel are easy
    enough so I don't really take much notice of what they say. However the
    Clymer manual is much better and I'm sure it's in there it show a
    picture of a guy bleeding the brakes on an abs with a Vacuum pump.
    
    You obviously replaced the pipes , Were they available from a BMW
    dealer or special order  from somewhere. Would be intrested as the k is
    in dry dock at the moment.
    
    Garry
2153.16A test...BROUGH::DAVIESNot Also, but ONLYMon Sep 27 1993 16:4821
 I too have had concerns about rubber brake hoses. I was at a bike show a few
years back and got a real good tip from a bloke at Girling. 

If you notice any movement in a hose when pressure is applied {with the engine
running for servo assist} when stationary then you can improve your braking
performance by fitting braided hoses.

I went home and tried it out on my Triumph. This has the single to Dual front
disk conversion. I like the feel that it gives me. The single disk was either 
OFF or ON no halfway house. Powering douple calipers from the same master
cylinder gave much more control. Applying the above test showed that the
original hose did move under the application of the brake whilst the hose
added to the second caliper did not. The latter was much more rigid. The pads
on that side also wore out quicker.

This winter I will be rebuilding the braking systems and replacing all the
hoses with steel braded types. A rebuild is required due to corrosion after
11 years.

Stephen D

2153.17Mintex 171PATTRN::MITCHELLD"Management is opaque"Tue Sep 28 1993 21:042
 Yep they are good on the road but are you suffering from brake fade ? I doubt
it!
2153.18mileageAYOU35::WARRENWed Sep 29 1993 11:267
re -1

But what sort of mileage could you expect to get from a set of Mintex ??

i have heard that it could be as little as 7000 miles - 
as I do about 700 a week, I do not want to change pads (at 30 quid a time)
every 10 weeks.
2153.19PATTRN::MITCHELLD"Management is opaque"Wed Sep 29 1993 13:008
it all depends how you drive a set of Mintex 171 have lasted 3 season  racing!!!
Mintex will last longer than ordinary ones if you drive hard. I bet I could
destroy a set of ordinary pads in less than 200 miles.
if your mileage doesnt involve repetitive hard braking 
(140 mph to zero tyres smoking that sort of hard) i.e. the Motorway 
they'll be fine.

	btw they contain asbestos
2153.20scuse the apparent ignorance but...AYOU35::WARRENWed Sep 29 1993 17:5413
>>>          	btw they contain asbestos



could you expand a little please ...?


- do they last longer as a result of the asbestos ???

-  health risk  (negligable ?)


warren
2153.21health risk yup but i use themPATTRN::MITCHELLD"Management is opaque"Thu Sep 30 1993 13:372
faded brakes are unheatlhy in competition car but I'm glad joe public doesnt
use them in any vast quantity anymore.
2153.22Take the yellow pages!UTROP1::BOSMAN_PFri Oct 01 1993 11:1421
    re .15
    The lines are availeble from any brake specialists shop and most larger
    motorcycle shops.
    Take your old lines with you and they'll custom make the new ones.
    Remember to get some black tie-wraps as well.
    Bleeding the system is quite easy and can be done without assistance.
    Do take your time as most air will rise to the main cilinder and bleed
    through the return hole on moving the lever. Only after all the rising
    bubles have escaped bleeding the calipers makes sense. 
    
    Even my current, OTR modified, Honda NX250 which had particularly
    sloppy and insensitive brakes was transformed. New lines, carefull
    routing and painstaiking air-bleeding has resulted in a rock-hard
    pressure point on the lever. Between first resistance and max squeeze
    pressure there is less than a centimeter travel at the end ball. Before
    this simple mod the flex allowed the lever to be pulled against the
    grip!
    Now I can feel how hard I was braking through my fingers at the lever 
    instead of the mud in my mouth. 
    
    Peter