Brake caliper hassle

Discussion in 'Car Repairs / Maintenance' started by Vicario, 10 Mar 2021.

  1. Vicario

    Vicario

    Joined:
    7 Sep 2008
    Messages:
    439
    Thanks Received:
    8
    Location:
    Kent
    Country:
    United Kingdom
    My garage has recommended changing a brake caliper on my Chevrolet Aveo auto (2012) if an intermittent fault keeps happening (lh nearside brake doesn't fully release and overheats, steering wheel wobbles). There are two types listed and mine is for a 256mm disc. But there are none available; plenty of 276mm ones though - would this fit my system? Or any advice about where to source a caliper for a 256mm disc? The garage says that they will fit it if I get it.
     
  2. Sponsored Links
  3. Mottie

    Mottie

    Joined:
    27 Feb 2017
    Messages:
    19,513
    Thanks Received:
    1,945
    Location:
    Essexshire
    Country:
    United Kingdom
    Plenty on ebay. I think I mentioned it before in your other thread.
     
  4. Vicario

    Vicario

    Joined:
    7 Sep 2008
    Messages:
    439
    Thanks Received:
    8
    Location:
    Kent
    Country:
    United Kingdom
    Hi again Mottie. Can you link me to one or two as I can't seem to find any. Thanks.
     
  5. Vicario

    Vicario

    Joined:
    7 Sep 2008
    Messages:
    439
    Thanks Received:
    8
    Location:
    Kent
    Country:
    United Kingdom
    I've done some more investigating. My car has 15 inch wheels whilst some Aveos have 14 inch. Is it safe to assume that the bigger wheel will need the 276mm calipers and that the smaller wheel takes the 256mm? Or doesn't it work like that?
     
  6. Burnerman

    Burnerman

    Joined:
    7 Feb 2008
    Messages:
    23,229
    Thanks Received:
    4,510
    Location:
    Northumberland
    Country:
    United Kingdom
    Sadly you cannot guarantee such a thing - although at times it may be applicable.
    Unfortunately you need the exact diameter of disc too as running clearances between disc edge and caliper are pretty tight. On occasion I have been able to replace the disc and caliper with bigger ones, but only as an axle set.
    Caliper repair kits are available so long as yours is serviceable - in other words the bleed nipple hasn't sheared off etc.
    John :)
     
  7. Mottie

    Mottie

    Joined:
    27 Feb 2017
    Messages:
    19,513
    Thanks Received:
    1,945
    Location:
    Essexshire
    Country:
    United Kingdom
  8. Vicario

    Vicario

    Joined:
    7 Sep 2008
    Messages:
    439
    Thanks Received:
    8
    Location:
    Kent
    Country:
    United Kingdom
    Here is a photo sent by my garage. Is the disc diameter measured including the brownish circle surrounding the shiny part? Any ideas from the photo as to size? I don't want to take the wheel off if I can avoid it. I have measured the distance between the nut threads (in the photo) as 45mm and on the car they are 70mm. On the photo the disc is 145mm. Those are the measurements on my enlarged image but your screen might be different - the ratios will be the same, of course. Anyone good at maths? I think I have the answer but let's see if we agree! Question - is this a 276mm or a 256mm disc. Have 12 A*s (sorry, grade 9s) for the correct answer!
     

    Attached Files:

  9. troutybrown

    troutybrown

    Joined:
    10 Dec 2007
    Messages:
    254
    Thanks Received:
    27
    Location:
    London
    Country:
    United Kingdom
    [​IMG]

    Measurement A is what you require
     
  10. Sponsored Links
  11. Peter.N.

    Peter.N.

    Joined:
    26 Sep 2006
    Messages:
    1,826
    Thanks Received:
    277
    Location:
    Dorset
    Country:
    United Kingdom
    Something to try. I have successfully used this a number of times. Fill a small oil can with brake fluid, using a small screwdriver, gently pull back the flexible piston gaiter/seal by sliding the screwdriver between them to reveal part of the piston, squirt some fluid into the space, preferably at the top, and it will run around the piston lubricating it all round, with a few operations it may well free off.

    Peter
     
  12. sxturbo

    sxturbo

    Joined:
    12 Jan 2014
    Messages:
    4,226
    Thanks Received:
    610
    Location:
    Essex
    Country:
    United Kingdom
    As it's intermittent I wonder if it is the caliper.

    I've had it in a couple of cars where the brakes were binding because of the caliper carrier (the bit where the pads sit) had corroded and was filled with brake dust. Removing it and cleaning it properly with a wire wheel cured the problem.

    No you can't just put calipers from a bigger disc on.

    You can send the caliper away for repair, plenty of places are able to do this and takes around 5 days, in my experience brake engineering were the best for this, it will need to be done via the garage or a motor factors.

    Troutybrown has advised how to measure the disc.

    Wheel size alone does not denote what size disc you have.
     
  13. DIYspanner

    DIYspanner

    Joined:
    17 Apr 2007
    Messages:
    2,225
    Thanks Received:
    104
    Country:
    United Kingdom
    A couple of good sources for calipers,

    TRW. Just enter the reg and select calipers.

    BigRed supply repair kits.

    By the way is it the caliper, sticking pads, flexii brake pipe or abs pump?

    The easiest way I know to measure the diameter of a brake disc is holding a ruler to the edge of the disc, parallel hub's axis, then measure between the ruler's edge and the hub centre, then x2 the measurement. May be a bit off because of rust on the disc edge but you can tap that off.
     
  14. cdbe

    cdbe

    Joined:
    22 Nov 2009
    Messages:
    1,489
    Thanks Received:
    261
    Location:
    Oldham
    Country:
    United Kingdom
    I'd change your garage. The ones I use are desperate to supply the parts (big mark up for them) - however, the benefit for the customer is that they warranty the parts.
    Your garage will fit the part you supply and then blame it if it doesn't solve your problems.
     
  15. Vicario

    Vicario

    Joined:
    7 Sep 2008
    Messages:
    439
    Thanks Received:
    8
    Location:
    Kent
    Country:
    United Kingdom
    I found this on the website of a company in Rochdale. It describes my problem exactly but I only get it affecting the nearside front brake. Would this issue affect all the brakes? - that's not entirely clear.

    I've found all the comments on this thread incredibly helpful and informative, so many thanks to evryone.


    301: Brakes bind – Only after driving for a while.

    Symptoms: Brakes are free at the start of a journey, but gradually bind or lock on as you drive.

    Cause: When braking, heat is generated. This heat is transferred to the brake fluid. As the temperature increases, the fluid expands. Under normal circumstances, this expanded fluid returns to the master cylinder reservoir. If the expanded fluid cannot return to the reservoir, pressure builds up and applies the brakes; and more heat and more pressure are generated. When the fluid cools down, pressure reduces and the brakes release.

    Solutions: Take your tools with you and drive the vehicle until the brakes bind on. (The more they bind on, the more time you will have to diagnose the problem). Follow these steps.

    Step 1
    With the brakes stuck on, slacken, by two to three threads, the nuts that hold the master cylinder to the servo. Then press and release the brake pedal. If the problem persists proceed to Step 2. If the brakes are free after you've done this, the problem lies with the servo or the mechanical links to the pedal. Check that an incorrectly adjusted brake light switch is not holding the pedal on slightly. If the pedal has a link rod to the servo, check that this is well lubricated and moves freely. If the problem is not caused by the brake light switch or by the link rod sticking, it's possible that the link rod or servo push rod has been adjusted incorrectly. Otherwise, the servo is probably faulty.

    Note
    Just in front of the master cylinder valve seals are small holes; these are compensating ports. With the brake pedal released, the master cylinder pistons should be fully home; otherwise the compensating ports will be blocked by the valve seals.

    Step 2
    Slacken one pipe at the master cylinder for each circuit in sequence. (Use a rag to stop fluid squirting everywhere because brake fluid works like paint stripper). This will release any pressure in that circuit. If the problem persists proceed to Step 3. If the brakes release now, then it's highly probable that the master cylinder seals have swollen through contamination and are blocking the compensating/relief ports.

    Step 3
    Feel each wheel and start with the hottest wheel/brake first. Careful, things will be very hot! Slacken the bleed nipple/s on the caliper or wheel cylinder. If the brakes do not release, proceed to the next hottest wheel and repeat. When the brakes release, the problem is a faulty flexible hose attached to that wheel.

    Note
    It is not uncommon for the inner wall of a flexible hose to collapse. When this happens, the collapsed wall can act like a one-way valve and can restrict the return of fluid.

    Step 4

    If the brakes are still stuck on, release the handbrake and start again!

    Important!
    Remember to re-tighten all pipes/unions, nuts/bolts and bleed nipples.
     
  16. Rad1o

    Rad1o

    Joined:
    27 Jun 2012
    Messages:
    278
    Thanks Received:
    13
    Location:
    Leics
    Country:
    United Kingdom
Loading...

Share This Page