• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Brakes lock up after 10-15 minutes of driving

troll

New member
Joined
Sep 9, 2012
This vehicle recently came into my possession with a bad master cylinder. On top of that, I found the left rear caliper to be seized. I decided to replace both, slap new rear pads on and bleed the entire system. Here's where it gets interesting...

Now when I drive the car, once the brake fluid gets hot the brakes start to drag at first then lock up altogether. Once the car cools off, I can drive off no problem. Today I tested for pushrod or pedal adjustment issues. I got things warm and locked up. Jacked up the rear end only to find that the new caliper spins free and the other 3 wheels are locked. I loosed the master cylinder anyway about 1/4 inch and there was no change.

I'm a bit lost. Not quite sure where the problem is. Any help would be appreciated.

77 242
 
Maybe you need front calipers too?

FWIW..............I once bought a 68 Impala that did this.
Turned out that the previous owner had used *hydraulic jack fluid* for/as brake fluid

I hope this is not the problem with your car. It'll require replacing all lines and brake componenets.
 
Did you bleed it really thoroughly and using correct procedure? If there is still some air in the system, that can cause the issue you're describing... start using the brakes, fluid gets hotter from normal driving, and the air in the fluid expands from the heat and the brakes begin to self-apply and drag a bit, that makes more heat, the air expands further, it becomes a sort of perpetual cycle, and pretty soon you're locked up and staying that way until things cool down enough for the brakes to relax. Can be exacerbated by sticky calipers that don't release all the way and cause some additional dragging that produces abnormal amounts of heat.

Or, could just be bad calipers, period -- likely enough if it already needed one plus a master, the fluid in there was pretty ugly and with two components already down, the other three (plus junction block too) might be in poor shape too. Heat can make a slightly sticky caliper more sticky via the expansion principles underlying the above as well. Start with a good thorough medieval bleeding first, though, if saving money is a priority.

I once heard of a similar problem with an old Subaru, too, but that one was different.... on that car, it turned out to be the hill-holder clutch mechanism that went on the fritz and was jamming the brakes on when nobody was asking it to. :roll: Likely not the issue with yours...
 
The strange part is that the car didn't do this before R&R'ing the M/C and L/R caliper.
 
The strange part is that the car didn't do this before R&R'ing the M/C and L/R caliper.

What symptoms *did* it have when you decided to replace those components? How did you determine that those two were problematic?

How does the pedal feel now, when it's working, before things start locking up?

Try bleeding again, very carefully....

Edit - here is one more idea that just occurred to me as I was thinking about this. I can't exactly recall how the dual-circuit setup is configured on a 200 series, but I believe I remember correctly that it is designed such that each of the two circuits operates on both front wheels and one of the rears. Your issue seems, in fact, to involve excessive pressure in both front wheels and one of the rears, which raises a flag. Natch, it also happens to involve all the wheels that don't have brand new calipers on it, so the failure circuit idea may well be a red herring and it might just need some calipers; however, I have seen on occasion situations with 240's where bleeding the brakes after a component replacement screws up the little slider valve in the junction block (which is designed to move and trip the brake failure light if it senses a loss of fluid in one of the two circuits). If that valve were to move while you were bleeding the brakes the first time, as it would and should have done, and if the valve were a little sticky and didn't make it all the way back to its correct resting location after you finished bleeding, could it affect the system's ability to relieve pressure in one of the two circuits and cause that circuit to fail to release quickly enough? Perhaps....

Is the "Brake Failure" light on the dash lit up? Does it work?

One way you could test this theory would be to get out your shop manual and find out which of the two circuits controls the three wheels that are giving you trouble. Then figure out which connections on the junction block are the relevant ones for those three wheels, get the system good and hot and locked up, then take your tubing wrench and one by one, loosen the brake line connections for those wheels on that circuit at the junction block. If opening the hydraulic fitting and relieving line pressure causes the brakes to unlock, then you know you have a hydraulic issue (perhaps compounded by the presence of air somewhere), either a bad junction block or a DOA master cylinder... On the other hand, if relieving hydraulic pressure does not cause the wheels to unlock, then you know that you need to put calipers on it.
 
Last edited:
The other cause of sticking brakes is bad flex lines that balloon up/restrict the flow of fluid back when you release the pedal. If your flex lines look old they are cheap to replace and you don't want one to split on you..
 
remove/replace master cylinder. Or, was that some witty humor that went right over my head?

Could have meant remove & rebuild existing M/C. Not a good thing to do on 240s/740 M/Cs

Rebuilt Volvo M/C have failed me twice I used them. Within 4 miles too. Yep was properly bench bled and system fully bled & purged.
 
You did go by the *proper bleed valve sequence* as listed by Volvo, or haynes, or bently Bilbe when you bled the system? Correct?

You did bleed until all new fluid came out of *each and every bleed valve* Correct?
 
What symptoms *did* it have when you decided to replace those components? How did you determine that those two were problematic?

How does the pedal feel now, when it's working, before things start locking up?

Try bleeding again, very carefully....

Edit - here is one more idea that just occurred to me as I was thinking about this. I can't exactly recall how the dual-circuit setup is configured on a 200 series, but I believe I remember correctly that it is designed such that each of the two circuits operates on both front wheels and one of the rears. Your issue seems, in fact, to involve excessive pressure in both front wheels and one of the rears, which raises a flag. Natch, it also happens to involve all the wheels that don't have brand new calipers on it, so the failure circuit idea may well be a red herring and it might just need some calipers; however, I have seen on occasion situations with 240's where bleeding the brakes after a component replacement screws up the little slider valve in the junction block (which is designed to move and trip the brake failure light if it senses a loss of fluid in one of the two circuits). If that valve were to move while you were bleeding the brakes the first time, as it would and should have done, and if the valve were a little sticky and didn't make it all the way back to its correct resting location after you finished bleeding, could it affect the system's ability to relieve pressure in one of the two circuits and cause that circuit to fail to release quickly enough? Perhaps....

Is the "Brake Failure" light on the dash lit up? Does it work?

One way you could test this theory would be to get out your shop manual and find out which of the two circuits controls the three wheels that are giving you trouble. Then figure out which connections on the junction block are the relevant ones for those three wheels, get the system good and hot and locked up, then take your tubing wrench and one by one, loosen the brake line connections for those wheels on that circuit at the junction block. If opening the hydraulic fitting and relieving line pressure causes the brakes to unlock, then you know you have a hydraulic issue (perhaps compounded by the presence of air somewhere), either a bad junction block or a DOA master cylinder... On the other hand, if relieving hydraulic pressure does not cause the wheels to unlock, then you know that you need to put calipers on it.

I knew the MC had to be replaced because the braking power was dismal and the pedal would random drop to the floor. When I pulled the wheels off, I found my RR pads needing replacement and my LR pads nice and meaty. Couldn't get any fluid out so I pulled the pads and go no movement from the pistons. So I replaced both.

Pedal feels fine, solid. Braking is fine when all is cold. Leading up to lock up, pedal feels the same but braking power is decreased.

The Brake Failure lights blinks occasionally when I step on the brakes but never illuminates fully. You seem to have a much more logical way of tracking this. I was just going to throw a RR caliper at it and if it still sticks, kick myself in the ass. The only reason I didn't assume calipers right off the bat is because of the triangular braking circuits.

I don't a have shop manual, it looks like I'll have to get one. But I have a hard time grasping how a bleed sequence can cause this issue. Even raised pressure from air expanding should relieve into the MC. This is my first Volvo though...
 
So I figured out which circuit controlled the RR caliper. I got the brakes locked up and loosened the line at the M/C that powered that circuit and my brakes free up. Does this mean I got a bad M/C? Or is there still a chance that the junction block is bad?
 
It looks like it has been suggested already, but a friend and I in highschool had this issue with a sticking brake caliper.

Master cylinder replaced. Caliper Relaced. Brakes uberbled. Ended up being the damn hose.
 
I've had this issue caused by a hose just like Mr Bill mentions above. It was also after the rear wheel cylinder and master cylinder had been replaced and the car still had the same issue. This car had drum brakes but the same kind of thing applies the rear hose had swelled internally and the fluid could go out to the wheel but not return so the pressure was released.
 
You should just Stage 0.. the M/C, all 4 calipers, and all 6 brake hoses along with new pads,all at one and the same time, along with frt wheel bearing repacking/regreasing or replacement whichever is needed.

Then purge bleed the entire brake sytem using the correct bleed valve sequence, until all clean fluid comes out of each & every caliper bleed valves.

Buy a "all new M/C" (not remanned)

Buy remanned calipers. Usually much better results/parts than trying to rebuild them yourself.
 
I knew the MC had to be replaced because the braking power was dismal and the pedal would random drop to the floor. When I pulled the wheels off, I found my RR pads needing replacement and my LR pads nice and meaty. Couldn't get any fluid out so I pulled the pads and go no movement from the pistons. So I replaced both.

Pedal feels fine, solid. Braking is fine when all is cold. Leading up to lock up, pedal feels the same but braking power is decreased.

The Brake Failure lights blinks occasionally when I step on the brakes but never illuminates fully. You seem to have a much more logical way of tracking this. I was just going to throw a RR caliper at it and if it still sticks, kick myself in the ass. The only reason I didn't assume calipers right off the bat is because of the triangular braking circuits.

I don't a have shop manual, it looks like I'll have to get one. But I have a hard time grasping how a bleed sequence can cause this issue. Even raised pressure from air expanding should relieve into the MC. This is my first Volvo though...

go HERE:
http://www.k-jet.org/documents/greenbooks/200-series/
and download the FACTORY GREENBOOK / MANUAL TP11405-4 Brakes Repairs and Maintenance 240, 260 1976

the READ IT and *then* you'll *KNOW*.....:nod:
 
Because of the brake warning light I suspect a leaking hose either in front or the rear brake hoses under the car on dvrs side. And possibly a leaking front/rear brake bia/junction block up behind the front driver's wheels mounted on the uniody chasis rail.

As previously stated. Just replace all 4 calipers and all 6 brake hoses(2 each front, and two under the car in rear) and see where that gets you.

Buy the IPSD SS brake hose kit. it's cheaper than just the front rubber hoses from Volvo

These 240s are at the age now that all the flexible rubber brake hoses are very old/aged/leaking and dangerous to drive with. Could save yours and/or loved ones life......................
 
on some master cly this can be caused by the actuator rod not being adjusted correctly (too long) therefore not letting the piston in the master cly return all the way, happens all the time in old VWs

I should have asked first " are the actuator rods adjustable on a 240?" lol
 
Back
Top