|
|
|
1993 240 w/ABS
I plan to change the driver's side front caliper later this week. As part of the procedure, do I need to bleed the whole system, or just the line to which the caliper is attached?
The opinions I can find vary so I'm turning to our experts that may have done this a few times in the past.
Thanks in advance.
|
|
-
|
|
|
Thank you for all the advice. I used the 'tape over the air hole' method. Worked perfectly. I got no drips over 24 hours. Very simple and easy.
Now I have other brake problems I'll post in another thread.
Thanks again.
|
|
-
|
|
|
Thanks everyone.
I just flushed the system a month ago, so everything is fresh. I gather that if I can keep the fluid from draining the MC, I should be ok without bleeding every corner.
Now for my next trick...
I need to disconnect the caliper for about 1.5 hours while I run across town to exchange it for a new one (don't want to make the trip twice) and don't want to loose fluid.
Will the tape over the MC cap air hole work as well as depressing the pedal a few inches? How about sealing off the end of the brake line with something until I'm able to return?
Thanks again.
|
|
-
|
|
|
I've left tape over the vent hole for 2-3 WEEKS while doing a large-brake conversion on the front of mine, and for 2-3 days while changing out a failed/leaking dual-diagonal circuit junction. If air can't get in the top, fluid can't get out the bottom. Much easier and more elegant than the "stick" - which also works. Just fill reservoir all the way to the top. And, of course, check to be sure it's doing it's job. I usually wipe the top of the cap off with alcohol or brake cleaner to be sure the tape stays stuck.
|
|
-
|
|
|
Just re-read your questions -- I switched to tape over the vent about 20 years ago -- I find it MUCH preferable to the stick method. As for 'plugging' the other end -- no need. You'll see when you break it open, if the reservoir is full up and you don't allow any air in the reservoir, no fluid can come out. Just like sticking your thumb over the top of a straw and pulling it out of your beverage. Nothing comes out the other end -- until you remove your thumb.
|
|
-
-
|
|
|
From my second post above - "I usually wipe the top of the cap off with alcohol or brake cleaner to be sure the tape stays stuck."
In the pic is masking tape -- I've used it and duct tape with equal effectiveness. Once I discovered this method, truth is I grab whatever tape happens to be handy. Keep in mind the physics involved - hydro "head" is creating lower pressure in the top of the reservoir, and atmospheric pressure is trying to push the tape 'into' the hole. As long as things are clean, my tape has always stayed in place. Fact is - even removing the piece I applied for the picture took a bit of digging with my finger nail...
|
|
-
-
|
|
|
Retired here - going on almost 5 years. I was chief utility operating officer for a regional natural gas distribution company. Happy to be done with a 24-7-365 shift. Wifey and I are working with an architect to build a new home, as we've always lived in someone else's design. And, finally, an attached garage for the DD's and a separate, detached 'working' garage with 12' ceilings and a LIFT. Taken pretty good care of the old temple over the years, but can't go on rolling around underneath one forever.
|
|
-
|
|
|
From my second post in the thread -- "I usually wipe the top of the cap off with alcohol or brake cleaner to be sure the tape stays stuck."
That's a piece of masking tape. I've used it or a small piece of duct tape with equal effectiveness. Keep in mind, the physics involved is PUSHING the piece of tape down.
|
|
-
|
|
|
I give up on this system - I type, hit submit, and then can't find the message. Hence the enhanced double post below.
|
|
-
|
|
Just curious Michael Yount, as you know I always use the stick and frequently recommend it. You say you "switched" methods. It would seem, once you had a stick cut to length, it would be more than a few seconds faster to grab and place it than to top off the reservoir and get tape to adhere over the cap's vent or be sure a stretch of plastic film under the cap did not rip as the cap is being tightened.
Yes, you don't have to remove the brake light fuse if you don't block the master. I just wonder why you would change your method. That's just a little harder for me to understand than keeping a method that works for you and not trying an alternative.
The principle of denying air entrance to the system is behind both methods. The stick just prevents it using the seals in the master cylinder. Either method, it would seem, is equally capable of preventing loss of fluid from an open line over the long term.
But I warn against gravity filling the new caliper with the bleed valve open by walking away to eat lunch. If the lines are clear, gravity and the atmosphere through that little vent hole can empty a reservoir in just a few minutes. If that happens, you don't have a choice anymore whether to bleed just one caliper or the whole car.
--
Art Benstein near Baltimore
If you think dogs can't count, try putting three dog biscuits in your pocket and then give him only two of them.
-Phil Pastoret
|
|
-
|
|
|
Don't know how it gets any easier than this.....it took longer to fire the "camera" up on the phone.
|
|
-
|
|
|
OK, understood. And your reservoir cap is cleaner than my toothbrush!
--
Art Benstein near Baltimore
My goal in life is to be as good of a person my dog already thinks I am.
|
|
-
|
|
|
Many, many (countless) cars/trucks over the years Art -- one size stick does not fit all. One piece of tape did. Never had a problem getting tape to stick/seal. And as you pointed out, no brake lights to worry about or deal with.
|
|
-
|
|
|
your choice whether to bleed all or not. it isn't required.
to bleed only the one caliper
1. remove brake light fuse
2. place a stick or equivalent between the brake pedal and the seat slider rail such that the pedal is depressed a few inches and use the rail. to ensure the pedal remains that way for the duration of the job.
3. now with brake line nut opened no fluid will escape the open line
4. remove caliper and change to new one, install pads
5. open bleeder and place a tray under the caliper
6. remove stick holding pedal down
at this point you can go eat your lunch and wait for gravity to bleed the caliper for you or give the pedal a few slight pushes to get the process going. once the fluid is streaming from the bleeder consistently close tighten and call it a day.
make sure the resevoir is full before removing the brake pedal stick
|
|
-
|
|
|
Put a piece of tape over the vent hole in the reservoir cap, fill the reservoir to the top and tighten the cap. When you break open the caliper line, you'll lose virtually no fluid at all -- and this will enable you to simple bleed the line(s) associated with the caliper you replaced.
Of course, if it's time for a system bleed anyhow.....
|
|
-
|
|
|
There are methods to keep new air from getting into the system when swapping a caliper (pretty easy with your single-line ABS calipers) but unless you are sure all the fluid has been flushed in in the last couple of years, it is time well spent to bleed each until the fluid looks like Bass Ale instead of Guinness Stout.
Just warning, if you use the pump, pump, hold method instead of a pressure or vac bleeder you need to avoid running the pedal through more travel than is used in normal braking. Put a block under it.
|
|
-
|
|
|
i'd bleed the whole car. volvo says change the brake fluid every 2 years, which lotsa people ignore. might've saved you a caliper purchase.
volvo started this in about 85, i think. been too long. i was in parts and we stocked approx 30 1330800 brake masters for the late 240s. service dept. started doing this to ALL volvos that came in for service. after about a year or so, we were stocking less than 10 due to lack of sales.
as far as 1 caliper, i would still do the whole car as it could've gotten air in the abs. as a pro, i would not let the car leave as the extra effort and brake fluid is not much more. good luck, chuck.
|
|
|
|
|
