1991 Volvo 740 front calipers

BRIAN50O

MEMBER
1991 VOLVO 740
4 CYL
2WD
AUTOMATIC
252,000 MILES

After driving 3 miles front calipers (the car is a 4 caliper system) start sticking, at 5 miles the front wheels lock solid. The car has abs and is a turbo. After turning car off and waiting 30 min, jack the car up the wheels spin freely. The calipers were replaced 25 miles ago and the new ones do the same thing. I've been a car mechanic and never had problems with abs, is it something in the abs locking the calipers up? Please help, I will make a donation, I would appreciate an answer ASAP. I have a hanes manual and it doesn't tell me anything. Thank you

2 Replies

CARADIODOC

MECHANIC
33,916 POSTS

Hi brian500. Welcome to the forum. When the calipers are still locked, crack the lines at the master cylinder to see if they release. If they do, suspect fluid contamination causing the lip seals to swell in the master cylinder. If they don't release, try opening a bleeder screw. If that lets them release, look for a metal bracket anchoring the middle of the rubber hose. I've run into a few Chryslers that have rust build up under the bracket where it is crimped around the hose. It will also cause a high, hard brake pedal. Pedal pressure will force the fluid through the constriction, but the fluid will take a long time to release. Simply opening the crimp a little with a channel lock pliers solves that problem. It usually only affects one wheel though, not both.

Caradiodoc